title stringlengths 12 150 | question_id int64 469 40.1M | question_score int64 2 5.52k | question_date stringdate 2008-08-02 15:11:16 2016-10-18 06:16:31 | answer_id int64 536 40.1M | answer_score int64 7 8.38k | answer_date stringdate 2008-08-02 18:49:07 2016-10-18 06:19:33 | tags listlengths 1 5 | question_body_md stringlengths 15 30.2k | answer_body_md stringlengths 11 27.8k |
|---|---|---|---|---|---|---|---|---|---|
How can I print variable and string on same line in Python? | 17,153,779 | 25 | 2013-06-17T17:58:08Z | 17,153,931 | 14 | 2013-06-17T18:06:51Z | [
"python",
"string",
"variables",
"printing"
] | I am using python to work out how many children would be born in 5 years if a child was born every 7 seconds. The problem is on my last line. How do I get a variable to work when I'm printing text either side of it?
Here is my code:
```
currentPop = 312032486
oneYear = 365
hours = 24
minutes = 60
seconds = 60
# seco... | two more
**The First one**
```
>>>births = str(5)
>>>print "there are " + births + " births."
there are 5 births.
```
When adding strings, they concatenate.
**The Second One**
Also the `format` (Python 2.6 and newer) method of strings is probably the standard way:
```
>>> births = str(5)
>>>
>>> print "there a... |
Flask error handling: "Response object is not iterable" | 17,153,978 | 6 | 2013-06-17T18:09:28Z | 17,154,441 | 8 | 2013-06-17T18:37:48Z | [
"python",
"rest",
"curl",
"flask"
] | I'm trying to set of a REST web service using Flask. I'm having a problem with the error handling `@app.errorhandler(404)`
```
#!flask/bin/python
from flask import Flask, jsonify, abort
app = Flask(__name__)
@app.errorhandler(404)
def not_found(error):
return jsonify({'error':'not found'}), 404
if __name__ == '... | ```
from flask import Flask, jsonify
app = Flask(__name__)
@app.errorhandler(404)
def not_found(error):
return jsonify({'error':'not found'}), 404
app.run()
```
With code above, `curl http://localhost:5000/` give me:
```
{
"error": "not found"
}
```
Are you using `flask.jsonify`? |
Unit testing an AsyncResult in celery | 17,154,146 | 8 | 2013-06-17T18:20:01Z | 17,155,922 | 10 | 2013-06-17T20:09:10Z | [
"python",
"django",
"unit-testing",
"celery"
] | I am trying to test some celery functionality in Django's unit testing framework, but whenever I try to check an AsyncResult the tests act like it was never started.
I know this code works in a real environment with RabbitMQ, so I was just wondering why it didn't work when using the testing framework.
Here is an exam... | When `CELERY_ALWAYS_EAGER` is `True`, the call to `apply_async()` is actually replaced with `apply()`. The result returned is an `EagerResult`, which already contains the result of your task.
So, yes, setting `ALWAYS_EAGER = True` disables the entire `AsyncResult` functionnality. The entire async process is bypassed, ... |
Multiple levels of keys and values in Python | 17,154,393 | 5 | 2013-06-17T18:34:55Z | 17,154,492 | 14 | 2013-06-17T18:40:59Z | [
"python",
"python-2.7",
"dictionary"
] | I wanted to know if the functionality i am trying to implement in python is possible.
I have a global hash called Creatures. Creatures contain sub-hashes called mammals, amphibians, birds, insects.
Mammals have sub-hashes called whales, elephants. Amphibians have sub-hashes called frogs, larvae. Birds have sub-hashes... | The value assigned to a key in a dictionary can itself be another dictionary
```
creatures = dict()
creatures['birds'] = dict()
creatures['birds']['eagle'] = dict()
creatures['birds']['eagle']['female'] = 0
creatures['birds']['eagle']['female'] += 1
```
You need to explicitly create each dictionary, though. Unlike Pe... |
Python - I'm getting an indentation error, but I don't see one. Tabs and spaces aren't mixed | 17,154,859 | 4 | 2013-06-17T19:02:57Z | 17,154,874 | 14 | 2013-06-17T19:03:38Z | [
"python",
"indentation"
] | My code is:
```
90 if needinexam > 100:
91 print "We are sorry, but you are unable to get an A* in this class."
92 else:
93 print "You need " + final + "% in your Unit 3 controlled assessment to get an A*"
94
95 elif unit2Done == "n":
96 ... | Try this:
```
elif unit2Done == "n":
pass # this is used as a placeholder, so the condition's body isn't empty
else:
print "Sorry. That's not a valid answer."
```
The problem here is that the body of the `unit2Done == "n"` condition can not be empty. In this case, a `pass` must be used as a kind of placeholde... |
Converting identifier naming between camelCase and underscores during JSON serialization/deserialization | 17,156,078 | 4 | 2013-06-17T20:17:29Z | 17,156,414 | 9 | 2013-06-17T20:38:53Z | [
"python",
"json"
] | I am working on a python/django application that serves as a web API server to its frontend counterpart. The data exchange between the server and the client is in JSON format with the use of XMLHttpRequest (Javascript). For those that are familiar with both Python and Javascript, you know that they have different ident... | One way to do it using regular expressions,
```
import re
camel_pat = re.compile(r'([A-Z])')
under_pat = re.compile(r'_([a-z])')
def camel_to_underscore(name):
return camel_pat.sub(lambda x: '_' + x.group(1).lower(), name)
def underscore_to_camel(name):
return under_pat.sub(lambda x: x.group(1).upper(), nam... |
Pandas DataFrame.unstack() Changes Order of Row and Column Headers | 17,156,662 | 6 | 2013-06-17T20:54:11Z | 17,157,110 | 7 | 2013-06-17T21:23:08Z | [
"python",
"pandas"
] | I have run into the following problem of sorting the row and column headers.
Here is how to reproduce this:
```
X =pd.DataFrame(dict(x=np.random.normal(size=100), y=np.random.normal(size=100)))
A=pd.qcut(X['x'], [0,0.25,0.5,0.75,1.0]) #create a factor
B=pd.qcut(X['y'], [0,0.25,0.5,0.75,1.0]) # create another factor
... | This seems like a little bit of a hack, but here goes:
```
In [11]: g_unstacked = g.unstack()
In [12]: g_unstacked
Out[12]:
y (-0.565, 0.12] (0.12, 0.791] (0.791, 2.57] [-2.177, -0.565]
x
(-0.068, 0.625] 0.389408 0.267252 0.283344 0.258337
(-0.892, -0.068] -0.1214... |
How to force virtualenv to install latest setuptools and pip from pypi? | 17,156,912 | 15 | 2013-06-17T21:07:56Z | 17,157,290 | 10 | 2013-06-17T21:37:34Z | [
"python",
"virtualenv",
"pip",
"setuptools",
"virtualenvwrapper"
] | Is it possible to force virtualenv to use the latest setuptools and pip available from pypi? Essentially, I'm looking for the ***opposite*** of the `--never-download` flag.
Currently, when I make a new virtualenv, it uses the local (old) versions that come bundled with virtualenv.
```
$ v.mk testvenv
New python execu... | It's not supported for security reasons.
> Using virtualenv.py as an isolated script (i.e. without an associated
> virtualenv\_support directory) is no longer supported for security
> reasons and will fail with an error. Along with this, --never-download
> is now always pinned to True, and is only being maintained in ... |
How to force virtualenv to install latest setuptools and pip from pypi? | 17,156,912 | 15 | 2013-06-17T21:07:56Z | 17,495,071 | 8 | 2013-07-05T18:40:22Z | [
"python",
"virtualenv",
"pip",
"setuptools",
"virtualenvwrapper"
] | Is it possible to force virtualenv to use the latest setuptools and pip available from pypi? Essentially, I'm looking for the ***opposite*** of the `--never-download` flag.
Currently, when I make a new virtualenv, it uses the local (old) versions that come bundled with virtualenv.
```
$ v.mk testvenv
New python execu... | You can upgrade pip after installing your virtualenv by using `pip install -U pip`.
I'm sure you could write a bootstrap-script to automate this step. |
Is there a way to set a default parameter equal to another parameter value? | 17,157,272 | 2 | 2013-06-17T21:36:00Z | 17,157,303 | 8 | 2013-06-17T21:38:16Z | [
"python",
"python-3.x"
] | For example, I have a basic method that will return a list of permutations.
```
import itertools
def perms(elements,setLength=elements):
data=[]
for x in range(elements):
data.append(x+1)
return(list(itertools.permutations(data,setLength)))
```
Now I understand, that in its current state this code... | No, function keyword parameter defaults are determined when the function is *defined*, not when the function is executed.
Set the default to `None` and detect that:
```
def perms(elements, setLength=None):
if setLength is None:
setLength = elements
```
If you need to be able to specify `None` as a argume... |
Get the error code from tweepy exception instance | 17,157,753 | 8 | 2013-06-17T22:13:09Z | 17,168,626 | 11 | 2013-06-18T12:16:40Z | [
"python",
"python-2.7",
"twitter",
"tweepy"
] | I'm new to python and I'm trying to use a library. It raises an exception, and I am trying to identify which one. This is what I am trying:
```
except tweepy.TweepError as e:
print e
print type(e)
print e.__dict__
print e.reason
print type(e.reason)
```
This is what I am getting:
```
[{u'message'... | How about this?
```
except tweepy.TweepError as e:
print e.message[0]['code'] # prints 34
print e.args[0][0]['code'] # prints 34
``` |
Centering x-tick labels between tick marks in matplotlib | 17,158,382 | 10 | 2013-06-17T23:17:09Z | 17,158,735 | 11 | 2013-06-18T00:03:51Z | [
"python",
"matplotlib",
"pandas"
] | I want to have the x-tick date labels centered between the tick marks, instead of centered about the tick marks as shown in the photo below.
I have read the documentation but to no avail - does anyone know a way to do this?
Here is everything that I... | One way to do it is to use the minor ticks. The idea is that you set the minor ticks so that they are located halfway between the major ticks, and you manually specify the labels.
For example:
```
import matplotlib.ticker as ticker
# a is an axes object, e.g. from figure.get_axes()
# Hide major tick labels
a.xaxis.... |
What is the way to delete words in Python list which does not have numbers? | 17,158,791 | 3 | 2013-06-18T00:12:36Z | 17,158,807 | 8 | 2013-06-18T00:14:52Z | [
"python",
"regex"
] | ```
a = ['in 1978 by', 'History', 'members', 'albums', 'June 4th, 1979', 'October 7,1986): "The Lounge', 'In 1984 the', 'early 1990s; prominent']
```
the above list have words like history, members which do not have numbers in them, so i want to delete them
```
# output would be
a = ['in 1978 by', 'June 4th, 1979'... | Keep the ones you want:
```
a = ['in 1978 by', 'History', 'members', 'albums', 'June 4th, 1979', 'October 7,1986): "The Lounge', 'In 1984 the', 'early 1990s; prominent']
new = [el for el in a if any(ch.isdigit() for ch in el)]
# ['in 1978 by', 'June 4th, 1979', 'October 7,1986): "The Lounge', 'In 1984 the', 'early 19... |
Excluding Fields in Django Class Based Views Not Working | 17,158,963 | 5 | 2013-06-18T00:36:39Z | 17,159,030 | 9 | 2013-06-18T00:45:23Z | [
"python",
"django",
"django-forms"
] | Boy, it feels like I've tried EVERYTHING here, and I just can't get this form to render properly (e.g. with a subset of fields). Here's the relevant items (extra items removed):
models.py:
```
class Response(models.Model):
public = models.BooleanField(default=False)
question = models.CharField(max_length=255,... | It looks like you need to specify `form_class` on your view:
```
class ResponseCreate(CreateView):
model = Response
form_class = ResponseForm
``` |
Change timezone of date-time column in pandas and add as hierarchical index | 17,159,207 | 13 | 2013-06-18T01:11:03Z | 17,159,276 | 14 | 2013-06-18T01:24:42Z | [
"python",
"timezone",
"dataframe",
"pandas",
"multi-index"
] | I have data with a time-stamp in UTC. I'd like to convert the timezone of this timestamp to 'US/Pacific' and add it as a hierarchical index to a pandas DataFrame. I've been able to convert the timestamp as an Index, but it loses the timezone formatting when I try to add it back into the DataFrame, either as a column or... | If you set it as the index, it's automatically converted to an Index:
```
In [11]: dat.index = pd.to_datetime(dat.pop('datetime'), utc=True)
In [12]: dat
Out[12]:
label value
datetime
2011-07-19 07:00:00 a 0
2011-07-19 08:00:00 a 1
2011-07-19 09:00:00 a 2
2011-07-19 07:... |
How to use select_for_update to 'get' a Query in Django? | 17,159,471 | 7 | 2013-06-18T01:55:37Z | 17,159,726 | 9 | 2013-06-18T02:36:13Z | [
"python",
"django",
"django-queryset"
] | As the Django Documentation says, `select_for_update` returns a `Queryset`. But `get` does not. Now I have a query which I am sure is going to return only one tuple. But I also need to acquire locks for this transaction. So I am doing something like:
```
ob = MyModel.objects.select_for_update().filter(some conditions)... | Just call `get`, slice it, etc. and save as usual. The lock is in place through the transaction.
```
ob = MyModel.objects.select_for_update().get(pk=1)
```
Any changes are committed at the end of the transaction (which by default through 1.5 is per-request) |
How to create a list of fields in django forms | 17,159,567 | 9 | 2013-06-18T02:11:17Z | 17,159,675 | 8 | 2013-06-18T02:26:57Z | [
"python",
"django",
"django-forms"
] | Is there any way to make a django forms class that actually holds an array of fields? I have a database that will pull up a variable number of questions to ask the user and each question will know how to define it's widget...etc, I just can't seem to hook this up to django forms.
I tried this:
```
class MyForm(forms.... | You may be able to use [formsets](https://docs.djangoproject.com/en/dev/topics/forms/formsets/) if your forms are identical (including their labels). e.g.
Question: ***\_*\_\_*\_*\_\_*\_*\_**
Question: ***\_*\_\_*\_*\_\_*\_*\_**
Question: ***\_*\_\_*\_*\_\_*\_*\_**
etc. I'm assuming each form contains only one fi... |
What is the ellipsis [...] in a Python list? | 17,160,162 | 152 | 2013-06-18T03:38:33Z | 17,160,180 | 83 | 2013-06-18T03:40:51Z | [
"python",
"list"
] | I was playing around in python. I used the following code in IDLE
```
p = [1, 2]
p[1:1] = [p]
print p
```
The output was
```
[1, [...], 2]
```
What is this [â¦]? Interestingly I could now use this as a list of list of list upto infinity i.e.
```
p[1][1][1]....
```
I could write the above as long as I wanted and... | It means that you created an infinite list nested inside itself, which can not be printed. `p` contains `p` which contains `p` ... and so on. The `[...]` notation is a way to let you know this, and to inform that it can't be represented! Take a look at @6502's answer to see a nice picture showing what's happening.
Now... |
What is the ellipsis [...] in a Python list? | 17,160,162 | 152 | 2013-06-18T03:38:33Z | 17,162,565 | 19 | 2013-06-18T07:06:16Z | [
"python",
"list"
] | I was playing around in python. I used the following code in IDLE
```
p = [1, 2]
p[1:1] = [p]
print p
```
The output was
```
[1, [...], 2]
```
What is this [â¦]? Interestingly I could now use this as a list of list of list upto infinity i.e.
```
p[1][1][1]....
```
I could write the above as long as I wanted and... | To the question "What's its use", here is a concrete example.
[Graph reduction](http://en.wikipedia.org/wiki/Graph_reduction) is an evaluation strategy sometime used in order to interpret a computer language. This is a common strategy for lazy evaluation, notably of functional languages.
The starting point is to buil... |
What is the ellipsis [...] in a Python list? | 17,160,162 | 152 | 2013-06-18T03:38:33Z | 17,163,521 | 273 | 2013-06-18T08:00:40Z | [
"python",
"list"
] | I was playing around in python. I used the following code in IDLE
```
p = [1, 2]
p[1:1] = [p]
print p
```
The output was
```
[1, [...], 2]
```
What is this [â¦]? Interestingly I could now use this as a list of list of list upto infinity i.e.
```
p[1][1][1]....
```
I could write the above as long as I wanted and... | This is what your code created
It's a list where the first and last elements are pointing to two numbers (1 and 2) and where the middle element is pointing to the list itself.
In Common Lisp when printing circular structures is enabled such an objec... |
Display python unittest results in nice, tabular form | 17,162,682 | 12 | 2013-06-18T07:12:28Z | 17,162,936 | 15 | 2013-06-18T07:25:34Z | [
"python",
"unit-testing",
"testing",
"python-unittest",
"test-reporting"
] | I am writing a Pythonic tool which validates the correctness of a certain system. Each validation is written as a Python [`unittest`](http://docs.python.org/2/library/unittest.html), and the report looks like:
```
test_exclude_list_not_empty (__main__.TestRepoLists)
Assert the the exclude list is not empty ... ok
test... | This is not exactly what you are asking, but there are several options for having a readable test output there:
* [HTMLTestRunner](http://tungwaiyip.info/software/HTMLTestRunner.html) generates easy to use HTML test reports in a tabular form. [Here](http://tungwaiyip.info/software/sample_test_report.html)'s a sample r... |
The for loop with letters instead of numbers | 17,163,113 | 3 | 2013-06-18T07:36:04Z | 17,163,204 | 7 | 2013-06-18T07:41:17Z | [
"python"
] | i know the for loop:
```
for i range(2, 6):
print i
```
gives this output:
```
2
3
4
5
```
can i also do this somehow with letters?
for example:
```
# an example for what i'm looking for
for i in range(c, h):
print i
c
d
f
g
``` | I think it's nicer to add `1` to `ord('g')` than using `ord('h')`
```
for code in range(ord('c'), ord('g') + 1):
print chr(code)
```
because what if you want to go to 'z', you need to know what follows 'z' . I bet you can type `+ 1` faster than you can look it up. |
Overwritten Methods don't contain self? | 17,164,028 | 4 | 2013-06-18T08:27:46Z | 17,164,156 | 8 | 2013-06-18T08:33:50Z | [
"python",
"python-2.7"
] | Here is an example I just played through on my machine:
```
$ python
Python 2.7.4 (default, Apr 19 2013, 18:28:01)
[GCC 4.7.3] on linux2
Type "help", "copyright", "credits" or "license" for more information.
# just a test class
>>> class A(object):
... def hi(self):
... print("hi")
...
>>> a = A()
>>> a.hi()
... | A method in a class referenced via an instance is bound to that instance, in your case:
```
In [3]: a.hi
Out[3]: <bound method A.hi of <__main__.A object at 0x218ab10>>
```
Compare to:
```
In [4]: A.hi
Out[4]: <unbound method A.hi>
```
So, to achieve the effect you probably want, do
```
In [5]: def hello(self):
... |
Regex nested parenthesis in python | 17,164,067 | 4 | 2013-06-18T08:29:54Z | 17,164,919 | 8 | 2013-06-18T09:10:40Z | [
"python",
"regex",
"text"
] | I have something like this:
```
Othername California (2000) (T) (S) (ok) {state (#2.1)}
```
Is there a regex code to obtain:
```
Othername California ok 2.1
```
I.e. I would like to keep the numbers within round parenthesis which are in turn within {} and keep the text "ok" which is within ().
I specifically need t... | ## Regex
```
(.+)\s+\(\d+\).+?(?:\(([^)]{2,})\)\s+(?={))?\{.+\(#(\d+\.\d+)\)\}
```
## Text used for test
```
Name1 Name2 Name3 (2000) {Education (#3.2)}
Name1 Name2 Name3 (2000) (ok) {edu (#1.1)}
Name1 Name2 (2002) {edu (#1.1)}
Name1 Name2 ... |
How can I make a Django form field contain only alphanumeric characters | 17,165,147 | 10 | 2013-06-18T09:22:25Z | 17,165,415 | 22 | 2013-06-18T09:35:56Z | [
"python",
"django"
] | I have this model
```
name = models.CharField(max_length=50, blank=True, null=True)
email = models.EmailField(max_length=50, unique=True)
```
I want that the user should not be able to use any other characters than alphanumerics in both fields.
Is there any way? | You would use a [validator](https://docs.djangoproject.com/en/1.9/ref/validators/) to limit what the field accepts. A [`RegexValidator`](https://docs.djangoproject.com/en/1.9/ref/validators/#regexvalidator) would do the trick here:
```
alphanumeric = RegexValidator(r'^[0-9a-zA-Z]*$', 'Only alphanumeric characters are ... |
Most efficient way of finding the next element in a tuple | 17,165,167 | 6 | 2013-06-18T09:23:28Z | 17,165,214 | 7 | 2013-06-18T09:25:31Z | [
"python",
"tuples",
"next"
] | I've got a system in which I often (but not constantly) have to find the next item in a tuple. I'm currently doing this like so:
```
mytuple = (2,6,4,8,7,9,14,3)
currentelement = 4
def f(mytuple, currentelement):
return mytuple[mytuple.index(currentelement) + 1]
nextelement = f(mytuple, currentelement)
```
All el... | Use a dict here, dicts provide `O(1)` lookup compared to `list.index` which is an `O(N)` operation.
And this will work for strings as well.
```
>>> lis = (2,6,4,8,7,9,14,3)
>>> dic = dict(zip(lis, lis[1:]))
>>> dic[4]
8
>>> dic[7]
9
>>> dic.get(100, 'not found') #dict.get can handle key errors
'not found'
```
A memo... |
Using Pandas to create DataFrame with Series, resulting in memory error | 17,165,340 | 9 | 2013-06-18T09:32:02Z | 17,169,776 | 10 | 2013-06-18T13:11:22Z | [
"python",
"numpy",
"pandas"
] | I'm using Pandas library for remote sensing time series analysis. Eventually I would like to save my DataFrame to csv by using chunk-sizes, but I run into a little issue. My code generates 6 NumPy arrays that I convert to Pandas Series. Each of these Series contains a lot of items
```
>>> prcpSeries.shape
(12626172,)
... | If you know each of these are the same length then you could create the DataFrame directly from the array and then append each column:
```
df = pd.DataFrame(prcpSeries, columns=['prcp'])
df['tmax'] = tmaxSeries
...
```
---
Note: you can also use the [`to_frame`](http://pandas.pydata.org/pandas-docs/stable/generated/... |
Matplotlib: show labels for minor ticks also | 17,165,435 | 6 | 2013-06-18T09:37:21Z | 17,167,748 | 10 | 2013-06-18T11:31:10Z | [
"python",
"matplotlib",
"plot",
"axis-labels"
] | In `matplotlib`, when I use a `log` scale on one axis, it might happen that that axis will have **no major ticks**, **only minor** ones. So this means **no labels** are shown for the whole axis.
How can I specify that I need labels also for minor ticks?
I tried:
```
plt.setp(ax.get_xticklabels(minor=True), visible=T... | You can use `set_minor_tickformatter` on the corresponding axis:
```
from matplotlib import pyplot as plt
from matplotlib.ticker import FormatStrFormatter
axes = plt.subplot(111)
axes.loglog([3,4,7], [2,3,4])
axes.xaxis.set_minor_formatter(FormatStrFormatter("%.2f"))
plt.xlim(1.8, 9.2)
plt.show()
```
![enter image d... |
Most efficient way of making an if-elif-elif-else statement when the else is done the most? | 17,166,074 | 62 | 2013-06-18T10:05:17Z | 17,166,144 | 63 | 2013-06-18T10:07:53Z | [
"python",
"performance",
"if-statement"
] | I've got a in if-elif-elif-else statement in which 99% of the time, the else statement is executed:
```
if something == 'this':
doThis()
elif something == 'that':
doThat()
elif something == 'there':
doThere()
else:
doThisMostOfTheTime()
```
This construct is done **a lot**, but since it goes over ever... | I'd create a dictionary :
```
options = {'this': doThis,'that' :doThat, 'there':doThere}
```
Now use just:
```
options.get(something, doThisMostOfTheTime)()
```
If `something` is not found in the `options` dict then `dict.get` will return the default value `doThisMostOfTheTime`
Some timing comparisons:
Script:
`... |
Most efficient way of making an if-elif-elif-else statement when the else is done the most? | 17,166,074 | 62 | 2013-06-18T10:05:17Z | 17,166,604 | 58 | 2013-06-18T10:29:24Z | [
"python",
"performance",
"if-statement"
] | I've got a in if-elif-elif-else statement in which 99% of the time, the else statement is executed:
```
if something == 'this':
doThis()
elif something == 'that':
doThat()
elif something == 'there':
doThere()
else:
doThisMostOfTheTime()
```
This construct is done **a lot**, but since it goes over ever... | The code...
```
options.get(something, doThisMostOfTheTime)()
```
...looks like it ought to be faster, but it's actually slower than the `if` ... `elif` ... `else` construct, because it has to call a function, which can be a significant performance overhead in a tight loop.
Consider these examples...
**1.py**
```
... |
Summing across rows of Pandas Dataframe | 17,166,601 | 7 | 2013-06-18T10:29:17Z | 17,166,768 | 9 | 2013-06-18T10:37:41Z | [
"python",
"pandas"
] | I have a data frame of records that looks something like this:
```
stocks = pd.Series(['A', 'A', 'B', 'C', 'C'], name = 'stock')
positions = pd.Series([ 100, 200, 300, 400, 500], name = 'positions')
same1 = pd.Series(['AA', 'AA', 'BB', 'CC', 'CC'], name = 'same1')
same2 = pd.Series(['AAA', 'AAA', 'BBB', 'CCC', 'CCC'],... | Step 1. Use [['positions']] instead of ['positions']:
```
In [30]: df2 = df.groupby(['stock','same1','same2'])[['positions']].sum()
In [31]: df2
Out[31]:
positions
stock same1 same2
A AA AAA 300
B BB BBB 300
C CC CCC 900
```
Step ... |
python how to "negate" value : if true return false, if false return true | 17,168,046 | 3 | 2013-06-18T11:47:43Z | 17,168,094 | 13 | 2013-06-18T11:49:54Z | [
"python",
"boolean",
"negate"
] | ```
if myval == 0:
nyval=1
if myval == 1:
nyval=0
```
Is there a better way to do a toggle in python, like a nyvalue = not myval ? | Use the [`not` boolean operator](http://docs.python.org/2/reference/expressions.html#boolean-operations):
```
nyval = not myval
```
`not` returns a *boolean* value (`True` or `False`):
```
>>> not 1
False
>>> not 0
True
```
If you must have an integer, cast it back:
```
nyval = int(not myval)
```
However, the pyt... |
python sqlite insert named parameters or null | 17,169,642 | 8 | 2013-06-18T13:05:52Z | 17,169,806 | 11 | 2013-06-18T13:12:33Z | [
"python",
"sqlite3",
"named-parameters"
] | I'm trying to insert data from a dictionary into a database using named parameters. I have this working with a simple SQL statement e.g.
```
SQL = "INSERT INTO status (location, arrival, departure) VALUES (:location, :arrival,:departure)"
dict = {'location': 'somewhere', 'arrival': '1000', 'departure': '1001'}
c.execu... | Use `None` to insert a `NULL`:
```
dict = {'location': 'somewhere', 'arrival': '1000', 'departure': None}
```
You can use a default dictionary and a generator to use this with `executemany()`:
```
defaults = {'location': '', 'arrival': None, 'departure': None}
c.executemany(SQL, ({k: d.get(k, defaults[k]) for k in ... |
Setting Transparency Based on Pixel Values in Matplotlib | 17,170,229 | 14 | 2013-06-18T13:31:22Z | 17,170,612 | 20 | 2013-06-18T13:46:58Z | [
"python",
"matplotlib",
"python-imaging-library"
] | I am attempting to use matplotlib to plot some figures for a paper I am working on. I have two sets of data in 2D numpy arrays: An ascii hillshade raster which I can happily plot and tweak using:
```
import matplotlib.pyplot as pp
import numpy as np
hillshade = np.genfromtxt('hs.asc', delimiter=' ', skip_header=6)[:,... | Just mask your "river" array.
e.g.
```
rivers = np.ma.masked_where(rivers == 0, rivers)
```
As a quick example of overlaying two plots in this manner:
```
import numpy as np
import matplotlib.pyplot as plt
import matplotlib.cm as cm
# Generate some data...
gray_data = np.arange(10000).reshape(100, 100)
masked_dat... |
Setting Transparency Based on Pixel Values in Matplotlib | 17,170,229 | 14 | 2013-06-18T13:31:22Z | 17,178,915 | 8 | 2013-06-18T21:04:48Z | [
"python",
"matplotlib",
"python-imaging-library"
] | I am attempting to use matplotlib to plot some figures for a paper I am working on. I have two sets of data in 2D numpy arrays: An ascii hillshade raster which I can happily plot and tweak using:
```
import matplotlib.pyplot as pp
import numpy as np
hillshade = np.genfromtxt('hs.asc', delimiter=' ', skip_header=6)[:,... | An alternate way to do this with out using masked arrays is to set how the color map deals with clipping values below the minimum of `clim` (shamelessly using Joe Kington's example):
```
import numpy as np
import matplotlib.pyplot as plt
import matplotlib.cm as cm
# Generate some data...
gray_data = np.arange(10000).... |
Python OpenCV load image from byte string | 17,170,752 | 11 | 2013-06-18T13:52:44Z | 17,170,855 | 26 | 2013-06-18T13:57:15Z | [
"python",
"image",
"opencv",
"byte"
] | I'm trying to load image from string like as PHP function `imagecreatefromstring`
How can I do that?
I have MySQL blob field image. I'm using **MySQLdb** and don't want create temporary file for working with images in PyOpenCV.
NOTE: need cv (not cv2) wrapper function | This is what I normally use to convert images stored in database to OpenCV images in Python.
```
import numpy as np
import cv2
from cv2 import cv
# Load image as string from file/database
fd = open('foo.jpg')
img_str = fd.read()
fd.close()
# CV2
nparr = np.fromstring(img_str, np.uint8)
img_np = cv2.imdecode(nparr, c... |
Python : split a list dynamically | 17,171,823 | 2 | 2013-06-18T14:41:42Z | 17,171,887 | 7 | 2013-06-18T14:44:16Z | [
"python",
"python-2.7"
] | I have a list `prodemployees` that looks like this :
```
['prd1 employe4 employe2', ' prd2 employe2']
```
I need the values of this list to dynamically create the "where" statement of a query, I need the output to be like this :
```
WHERE (product = 'prd1' AND employe IN ('employe4','employe2'))
OR
(product = 'prd2'... | You have a list after splitting, you can *slice* that list to get a sublist:
```
for prod_emp in prodemployees:
prod_emp = prod_emp.split()
prod, emp = prod_emp[0], prod_emp[1:]
```
Here `prod` is set to the first element of your split string, `emp` to a list of all elements but the first:
```
>>> prodemploy... |
Why are some Python strings are printed with quotes and some are printed without quotes? | 17,171,889 | 6 | 2013-06-18T14:44:31Z | 17,171,965 | 13 | 2013-06-18T14:47:54Z | [
"python",
"string",
"representation"
] | I have a problem with string representations. I am trying to print my object and I sometimes get single quotes in the output. Please help me to understand why it happens and how can I print out the object without quotes.
Here is my code:
```
class Tree:
def __init__(self, value, *children):
self.value = v... | `repr` on a string gives quotes while `str` does not. e.g.:
```
>>> s = 'foo'
>>> print str(s)
foo
>>> print repr(s)
'foo'
```
Try:
```
def __repr__(self):
if len(self.children) == 0:
return '%s' %self.value
else:
childrenStr = ' '.join(map(str, self.children)) #str, not repr!
return... |
Using Python's multiprocessing.Process class | 17,172,878 | 11 | 2013-06-18T15:27:43Z | 17,220,739 | 20 | 2013-06-20T18:09:17Z | [
"python",
"class",
"multiprocessing"
] | This is a newbie question:
A class is an object, so I can create a class called `pippo()` and inside of this add function and parameter, I don't understand if the functions inside of `pippo` are executed from up to down when I assign `x=pippo()` or I must call them as `x.dosomething()` outside of `pippo`.
Working wit... | I often wondered why Python's doc page on [multiprocessing](http://docs.python.org/2/library/multiprocessing.html) only shows the "functional" approach (using `target` parameter). Probably because terse, succinct code snippets are best for illustration purposes. For small tasks that fit in one function, I can see how t... |
Is a specific timezone using DST right now? | 17,173,298 | 6 | 2013-06-18T15:46:33Z | 17,173,657 | 8 | 2013-06-18T16:01:18Z | [
"python",
"time",
"timezone",
"pytz"
] | How would I get my python script to check whether or not a specific timezone that is stored in a variable using DST right now?
My server is set to UTC.
So I have
say for instance
```
zonename = Pacific/Wallis
```
I want to run the query about if it is using DST right now and have the reply come back as either true of... | ```
from pytz import timezone
from datetime import datetime
zonename = "Pacific/Wallis"
now = datetime.now(tz=timezone(zonename))
dst_timedelta = now.dst()
### dst_timedelta is offset to the winter time,
### thus timedelta(0) for winter time and timedelta(0, 3600) for DST;
### it returns None if timezone is not set
... |
Python issues with return statement | 17,173,822 | 3 | 2013-06-18T16:08:52Z | 17,173,844 | 9 | 2013-06-18T16:09:56Z | [
"python",
"return"
] | Hello I'm very new to python and was wondering if you could help me with something.
I've been playing around with this code and can't seem to get it to work.
```
import math
def main():
if isPrime(2,7):
print("Yes")
else:
print("No")
def isPrime(i,n):
if ((n % i == 0) and (i <= math.s... | You are discarding the return value for the recursive call:
```
def isPrime(i,n):
if ((n % i == 0) and (i <= math.sqrt(n))):
return False
if (i >= math.sqrt(n)):
print ("is Prime: ",n)
return True
else:
# No return here
isPrime(i+1,n)
```
You want to propagate the v... |
Can Alembic Autogenerate column alterations? | 17,174,636 | 10 | 2013-06-18T16:54:53Z | 17,176,843 | 17 | 2013-06-18T19:03:41Z | [
"python",
"postgresql",
"sqlalchemy",
"flask",
"alembic"
] | I was able to use
`alembic --autogenerate` for when adding / removing columns.
However, when I wanted to modify for example a "url" column from 200 characters to 2000 characters, it doesn't detect the change.
How can I make Alembic (using SQLAlchemy), detect changes and autogenerate scripts to my model's "sizes" of v... | Looks like I found the answer on reddit's /r/flask.
<http://www.reddit.com/r/flask/comments/1glejl/alembic_autogenerate_column_changes/cale9o0>
Just add "compare\_type=True" to context.configure() parameters inside your env.py's "run\_migrations\_online" function.
```
context.configure(
connectio... |
Can model views in Flask-Admin hyperlink to other model views? | 17,174,707 | 13 | 2013-06-18T16:59:30Z | 17,184,281 | 17 | 2013-06-19T06:28:40Z | [
"python",
"flask"
] | Suppose we have a model, Foo, that references another model, User - and Flask-Admin views for both.
On the Foo admin view page (e.g. something like the first screenshot at <http://mrjoes.github.io/2012/08/27/flask-admin-102.html> ), I would like the entries in the User column to be link to the corresponding User model... | Use `column_formatters` for this: <https://flask-admin.readthedocs.org/en/latest/api/mod_model/#flask.ext.admin.model.BaseModelView.column_formatters>
Idea is pretty simple: for a field that you want to display as hyperlink, either generate a HTML string and wrap it with Jinja2 `Markup` class (so it won't be escaped i... |
Can model views in Flask-Admin hyperlink to other model views? | 17,174,707 | 13 | 2013-06-18T16:59:30Z | 17,191,125 | 25 | 2013-06-19T12:25:29Z | [
"python",
"flask"
] | Suppose we have a model, Foo, that references another model, User - and Flask-Admin views for both.
On the Foo admin view page (e.g. something like the first screenshot at <http://mrjoes.github.io/2012/08/27/flask-admin-102.html> ), I would like the entries in the User column to be link to the corresponding User model... | Some example code based on Joes' answer:
```
class MyFooView(ModelView):
def _user_formatter(view, context, model, name):
return Markup(
"<a href='%s'>%s</a>" % (
url_for('user.edit_view', id=model.user.id),
model.user
)
) if model.user else ... |
Python JSON String (containing hex) to HEX | 17,175,395 | 3 | 2013-06-18T17:37:37Z | 17,175,426 | 7 | 2013-06-18T17:39:28Z | [
"python",
"json",
"string",
"hex"
] | I'm trying to get random hex value between range of hexes:
`random.randint(0xfff000, 0xffffff)`
I got the range limits from JSON, as a string.
`{"range": "0xfff000,0xffffff"}`
How can I convert these strings(after splitting) to hexadecimal values? | Use the built-in [`int()`](http://docs.python.org/2/library/functions.html#int) function with a base of `16`:
```
>>> int('0xfff000', 16)
16773120
>>> int('0xfff000', 16) == 0xfff000
True
``` |
How can I send a message to a group conversation with Skype4Py in Python | 17,176,009 | 4 | 2013-06-18T18:15:21Z | 17,176,358 | 8 | 2013-06-18T18:36:33Z | [
"python",
"python-2.7",
"group",
"sendmessage",
"skype4py"
] | I've been trying to get my script to send a message to a group conversation in Skype using the Skype4Py library, the only way I am currently able to send messages is to specific users.
```
import Skype4Py
Skype = Skype4Py.Skype()
Skype.Attach()
Skype.SendMessage('namehere','testmessage')
```
Does anyone know how I ca... | The following little script should work. (Assuming you already have a group chat open)
```
def sendGroupChatMessage():
"""
Send Group Chat Messages.
"""
import Skype4Py as skype
skypeClient = skype.Skype()
skypeClient.Attach()
for elem in skypeClient.ActiveChats:
if len(elem.Members... |
Python - get all permutation of a list w/o repetitions | 17,176,887 | 4 | 2013-06-18T19:06:07Z | 17,176,932 | 9 | 2013-06-18T19:08:50Z | [
"python",
"list",
"combinations",
"permutation",
"itertools"
] | I know that I can use itertools.permutation to get all permutation of size r.
But, for `itertools.permutation([1,2,3,4],3)` it will return `(1,2,3)` as well as `(1,3,2)`.
1. I want to filter those repetitions (i.e obtain combinations)
2. Is there a simple way to get all permutations (of all lengths)?
3. How can I conv... | Use [`itertools.combinations`](http://docs.python.org/2/library/itertools.html#itertools.combinations) and a simple loop to get combinations of all size.
`combinations` return an iterator so you've to pass it to `list()` to see it's content(or consume it).
```
>>> from itertools import combinations
>>> lis = [1, 2, 3... |
convert xml to python dict | 17,177,109 | 3 | 2013-06-18T19:19:15Z | 17,177,485 | 10 | 2013-06-18T19:40:50Z | [
"python",
"xml",
"parsing",
"dictionary",
"xml-parsing"
] | I'm trying to make a dict class to process an xml but get stuck, I really run out of ideas. If someone could guide on this subject would be great.
code developed so far:
```
class XMLResponse(dict):
def __init__(self, xml):
self.result = True
self.message = ''
pass
def __setattr__(sel... | You can make use of [`xmltodict`](https://github.com/martinblech/xmltodict) module:
```
import xmltodict
message = """<?xml version="1.0"?><note><to>Tove</to><from>Jani</from><heading>Reminder</heading><body>Don't forget me this weekend!</body></note>"""
print xmltodict.parse(message)['note']
```
which produces an `... |
Get worker ID in Celery | 17,177,491 | 6 | 2013-06-18T19:41:20Z | 17,179,198 | 8 | 2013-06-18T21:22:35Z | [
"python",
"celery"
] | I want to use Celery to run jobs on a GPU server with four Tesla cards. I run the Celery worker with a pool of four workers such that each card always runs one job.
My problem is how to instruct the workers to each claim one GPU. Currently I rely on the assumption that the worker processes should all have contiguous p... | If you are using `CELERYD_POOL = 'processes'`, the worker pool is handled by `billiard`, which does happen to expose its 0-based process index:
```
from billiard import current_process
from celery import task
@task
def print_info():
# This will print an int in [0..concurrency[
print current_process().index
``... |
How to remove all non-integers from a string? (Python) | 17,178,068 | 3 | 2013-06-18T20:15:20Z | 17,178,086 | 11 | 2013-06-18T20:16:22Z | [
"python",
"regex",
"string"
] | I'm pretty new to python. I have a question. Say for example when I read a line from a file I have a string that looks like this.
```
thestring = '000,5\r\n'
```
How do I remove all non-integers from this string and then convert this string into an integer itself? Thanks! | Using `str.translate`, this is probably the fastest way to do this:
```
>>> strs = '000,5\r\n'
>>> from string import ascii_letters, punctuation, whitespace
>>> ignore = ascii_letters + punctuation + whitespace
>>> strs.translate(None, ignore)
'0005'
```
Using `regex`:
```
>>> import re
>>> re.sub(r'[^\d]+','',s... |
Python (2.7): Why is there a performance difference between the following 2 code snippets that implement the intersection of two dictionaries | 17,179,351 | 3 | 2013-06-18T21:32:01Z | 17,179,441 | 8 | 2013-06-18T21:37:12Z | [
"python",
"performance",
"python-2.7"
] | The following 2 code snippets (A & B) both return the intersection of 2 dictionaries.
Both of following 2 code snippets should run in O(n) and output the same results. However code snippet B which is pythonic, seems to run faster. **These code snippets come from the Python Cookbook.**
Code Snippet A:
```
def simplew... | They don't quite do the same thing; the first one does a lot more work:
* It looks up the `.has_key()` and `.append()` methods each time in the loop, and then calls them. This requires a stack push and pop for each call.
* It appends each new element to a list one by one. The Python list has to be grown dynamically to... |
How to Swap First and Last Characters from Input in Python | 17,179,584 | 2 | 2013-06-18T21:47:58Z | 17,179,607 | 8 | 2013-06-18T21:49:32Z | [
"python",
"python-3.x"
] | I am brand new to programming, learning Python3 from an online course. This exercise asks me to write a program which reads a string using `input()`, and outputs the same string but with the first and last character exchanged (example: Fairy becomes yairF). There is likely a simpler way to do this with more advanced fu... | Try this:
```
>>> temp = "abcde"
>>> temp[1:-1]
'bcd'
>>> temp[-1:] + temp[1:-1] + temp[:1]
'ebcda'
>>>
```
In short, python has magnificent string slicing syntax. You can do magic with it. |
Python: 'string index out of range' | 17,179,808 | 2 | 2013-06-18T22:03:04Z | 17,179,822 | 7 | 2013-06-18T22:04:29Z | [
"python"
] | I had a quick search but couldn't find anything that helped my problem.
I'm trying to make a program that takes the first 5 numbers and sources their product, and if that product is the largest found thus far it is set as such.
My code is:
```
string = str(integer)
x = 0
largest = 0
stringlength = len(string)
whil... | ```
string = str(integer)
x = 0
largest = 0
stringlength = len(string)
while x < stringlength-4: # going to -5 would be out of rangue
a = int(string[x])
b = int(string[x+1])
c = int(string[x+2])
d = int(string[x+3])
e = int(string[x+4])
if (a*b*c*d*e > largest):
largest = a*b*c*d*e
... |
Mock vs MagicMock | 17,181,687 | 55 | 2013-06-19T01:49:02Z | 17,182,790 | 25 | 2013-06-19T04:16:03Z | [
"python",
"mocking"
] | My understanding is that *MagicMock* is a superset of *Mock* that automatically does "magic methods" thus seamlessly providing support for lists, iterations and so on... Then what is the reason for plain *Mock* existing? Isn't that just a stripped down version of *MagicMock* that can be practically ignored? Does *Mock*... | With Mock you *can* mock magic methods but you have to define them. MagicMock has ["default implementations of most of the magic methods."](http://www.voidspace.org.uk/python/mock/magicmock.html#mock.MagicMock).
If you don't need to test any magic methods, Mock is adequate and doesn't bring a lot of extraneous things ... |
Mock vs MagicMock | 17,181,687 | 55 | 2013-06-19T01:49:02Z | 23,012,876 | 45 | 2014-04-11T12:42:33Z | [
"python",
"mocking"
] | My understanding is that *MagicMock* is a superset of *Mock* that automatically does "magic methods" thus seamlessly providing support for lists, iterations and so on... Then what is the reason for plain *Mock* existing? Isn't that just a stripped down version of *MagicMock* that can be practically ignored? Does *Mock*... | ### What is the reason for plain *Mock* existing?
Mock's author, Michael Foord, addressed [a very similar question at Pycon 2011 (31:00)](http://pyvideo.org/video/392/pycon-2011--testing-with-mock):
> **Q:** Why was MagicMock made a separate thing rather than just folding the ability into the default mock object?
>
>... |
Mock vs MagicMock | 17,181,687 | 55 | 2013-06-19T01:49:02Z | 27,307,550 | 8 | 2014-12-05T01:56:25Z | [
"python",
"mocking"
] | My understanding is that *MagicMock* is a superset of *Mock* that automatically does "magic methods" thus seamlessly providing support for lists, iterations and so on... Then what is the reason for plain *Mock* existing? Isn't that just a stripped down version of *MagicMock* that can be practically ignored? Does *Mock*... | To begin with, `MagicMock` is a subclass of `Mock`.
```
class MagicMock(MagicMixin, Mock)
```
As a result, MagicMock provides everything that Mock provides and more. Rather than thinking of Mock as being a stripped down version of MagicMock, think of MagicMock as an extended version of Mock. This should address your ... |
How do I iterate through the alphabet in Python, Please? | 17,182,656 | 24 | 2013-06-19T03:59:17Z | 17,182,670 | 43 | 2013-06-19T04:00:45Z | [
"python",
"python-2.7",
"alphabet"
] | Can I simply ++ a char? what is an efficient way of doing this? I want to iterate through urls that have the www.website.com/term/#, www.website.com/term/a, www.website.com/term/b, www.website.com/term/c, www.website.com/term/d ... www.website.com/term/z format | You can use [`string.ascii_lowercase`](http://docs.python.org/2/library/string.html#string.ascii_lowercase) which is simply a convenience string of lowercase letters,
```
>>> from string import ascii_lowercase
>>> for c in ascii_lowercase:
... # append to your url
``` |
How do I iterate through the alphabet in Python, Please? | 17,182,656 | 24 | 2013-06-19T03:59:17Z | 17,182,751 | 11 | 2013-06-19T04:10:21Z | [
"python",
"python-2.7",
"alphabet"
] | Can I simply ++ a char? what is an efficient way of doing this? I want to iterate through urls that have the www.website.com/term/#, www.website.com/term/a, www.website.com/term/b, www.website.com/term/c, www.website.com/term/d ... www.website.com/term/z format | In addition to `string.ascii_lowercase` you should also take a look at the [`ord`](http://docs.python.org/2/library/functions.html#ord) and [`chr`](http://docs.python.org/2/library/functions.html#chr) built-ins. `ord('a')` will give you the ascii value for 'a' and `chr(ord('a'))` will give you the character back.
Usin... |
SCons- *** No SConstruct file found | 17,182,799 | 3 | 2013-06-19T04:17:03Z | 17,185,787 | 8 | 2013-06-19T07:53:35Z | [
"python",
"scons"
] | Installed SCons using
# cd scons-2.3.0
# python setup.py install
After Installation, when i try to run scons , got the below error.
scons: *\** No SConstruct file found.
File "/usr/local/lib/scons-2.3.0/SCons/Script/Main.py", line 905, in \_main
How to overcome this ??? | There are 3 ways to specify the SConstruct file when using SCons, as follows:
* Execute `scons` from the root of the project, where there should be a SConstruct file. This is the most standard way.
* From a subdirectory of the project, where there should be a SConsctruct file at the root, execute `scons` with one of t... |
Python repeat string | 17,183,259 | 12 | 2013-06-19T05:07:38Z | 17,183,278 | 24 | 2013-06-19T05:09:06Z | [
"python"
] | I am trying string repetition in Python.
```
#!/bin/python
str = 'Hello There'
print str[:5]*2
```
**Output**
> HelloHello
**Required Output**
> Hello Hello
Can anyone please point me in the right direction .
Python version: 2.6.4 | ```
string = 'Hello There'
print ' '.join([string[:5]] * 2)
``` |
how to remove task from celery with redis broker? | 17,184,244 | 4 | 2013-06-19T06:25:14Z | 17,250,543 | 13 | 2013-06-22T12:07:57Z | [
"python",
"celery",
"celery-task",
"celeryd"
] | I Have add some wrong `task` to a `celery` with redis `broker`
but now I want to remove the incorrect `task` and I can't find any way to do this
Is there some commands or some api to do this ? | I know two ways of doing so:
1) Delete queue directly from broker. In your case it's Redis. There are two commands that could help you: **llen** (to find right queue) and **del** (to delete it).
2) Start celery worker with **--purge** or **--discard** options. Here is help:
```
--purge, --discard Purges all waiti... |
Python: get a checkbox - the easiest way | 17,185,134 | 9 | 2013-06-19T07:19:58Z | 17,186,472 | 7 | 2013-06-19T08:30:53Z | [
"python",
"user-interface",
"tkinter"
] | or perhaps the lazy way..
I'm looking for a python module that has some build-in GUI methods to get quick user inputs - a very common programming case. Has to work on windows 7
**My ideal case**
```
import magicGUImodule
listOfOptions = ["option 1", "option 2", "option 3"]
choosenOptions = magicGUImodule.getChecklis... | Here's a simple example using `Tkinter` (instead of checkboxes `listbox` with multiple selection is used):
```
from Tkinter import *
def callback():
print listbox.selection_get()
master.destroy()
master = Tk()
listbox = Listbox(master, selectmode=MULTIPLE)
for option in ["option 1", "option 2", "option 3"... |
Python: get a checkbox - the easiest way | 17,185,134 | 9 | 2013-06-19T07:19:58Z | 17,330,144 | 7 | 2013-06-26T20:46:18Z | [
"python",
"user-interface",
"tkinter"
] | or perhaps the lazy way..
I'm looking for a python module that has some build-in GUI methods to get quick user inputs - a very common programming case. Has to work on windows 7
**My ideal case**
```
import magicGUImodule
listOfOptions = ["option 1", "option 2", "option 3"]
choosenOptions = magicGUImodule.getChecklis... | [Easygui](http://easygui.sourceforge.net/) module is **exactly** what you need:
```
import easygui as eg
question = "This is your question"
title = "This is your window title"
listOfOptions = ["option 1", "option 2", "option 3"]
choice = eg.multchoicebox(question , title, listOfOptions)
```
`choice` will return a l... |
How to run Ansible without specifying the inventory but the host directly? | 17,188,147 | 25 | 2013-06-19T09:50:23Z | 18,255,256 | 58 | 2013-08-15T14:48:10Z | [
"python",
"ansible"
] | I want to run Ansible in Python without specifying the inventory file through (ANSIBLE\_HOST) but just by:
```
ansible.run.Runner(
module_name='ping',
host='www.google.com'
)
```
I can actually do this in fabric easily but just wonder how to do this in Python. On the other hand, documentation of the Ansible API f... | Surprisingly, the trick is to append a `,`
```
# Host and IP address
ansible all -i example.com,
ansible all -i 93.184.216.119,
```
or
```
# Requires 'hosts: all' in your playbook
ansible-playbook -i example.com, playbook.yml
```
The host parameter preceding the `,` can be either a hostname or an IPv4/v6 address. |
How to run Ansible without specifying the inventory but the host directly? | 17,188,147 | 25 | 2013-06-19T09:50:23Z | 29,315,404 | 11 | 2015-03-28T09:07:55Z | [
"python",
"ansible"
] | I want to run Ansible in Python without specifying the inventory file through (ANSIBLE\_HOST) but just by:
```
ansible.run.Runner(
module_name='ping',
host='www.google.com'
)
```
I can actually do this in fabric easily but just wonder how to do this in Python. On the other hand, documentation of the Ansible API f... | I know this question is really old but think that this little trick might helpful for future users who need help for this:
```
ansible-playbook -i '10.254.3.133,' site.yml
```
if you run for local host:
```
ansible-playbook -i 'localhost,' --connection=local site.yml
```
The trick is that after ip address/dns name,... |
Subprocess.Popen: cloning stdout and stderr both to terminal and variables | 17,190,221 | 6 | 2013-06-19T11:38:25Z | 17,190,793 | 8 | 2013-06-19T12:08:56Z | [
"python",
"python-3.x",
"subprocess",
"popen"
] | Is it possible to modify code below to have printout from 'stdout 'and 'stderr':
* printed on the **terminal** (in real time),
* and finally stored in **outs** and **errs** variables?
The code:
```
#!/usr/bin/python3
# -*- coding: utf-8 -*-
import subprocess
def run_cmd(command, cwd=None):
p = subprocess.Popen... | You could spawn threads to read the stdout and stderr pipes, write to a common queue, and append to lists. Then use a third thread to print items from the queue.
```
import time
import Queue
import sys
import threading
import subprocess
PIPE = subprocess.PIPE
def read_output(pipe, funcs):
for line in iter(pipe.r... |
Subprocess.Popen: cloning stdout and stderr both to terminal and variables | 17,190,221 | 6 | 2013-06-19T11:38:25Z | 25,960,956 | 10 | 2014-09-21T15:49:11Z | [
"python",
"python-3.x",
"subprocess",
"popen"
] | Is it possible to modify code below to have printout from 'stdout 'and 'stderr':
* printed on the **terminal** (in real time),
* and finally stored in **outs** and **errs** variables?
The code:
```
#!/usr/bin/python3
# -*- coding: utf-8 -*-
import subprocess
def run_cmd(command, cwd=None):
p = subprocess.Popen... | To capture and display at the same time both stdout and stderr from a child process line by line in a single thread, you could use asynchronous I/O:
```
#!/usr/bin/env python3
import asyncio
import os
import sys
from asyncio.subprocess import PIPE
@asyncio.coroutine
def read_stream_and_display(stream, display):
"... |
How to obtain a gaussian filter in python | 17,190,649 | 8 | 2013-06-19T12:00:29Z | 17,201,686 | 14 | 2013-06-19T21:27:45Z | [
"python",
"matlab",
"numpy",
"gaussian"
] | I am using python to create a gaussian filter of size 5x5.
I saw this post [here](http://stackoverflow.com/questions/11209115/creating-gaussian-filter-of-required-length-in-python) where they talk about a similar thing but I didn't find the exact way to get equivalent python code to matlab function `fspecial('gaussian'... | In general terms if you really care about getting the the exact same result as MATLAB, the easiest way to achieve this is often by looking directly at the source of the MATLAB function.
In this case, `edit fspecial`:
```
...
case 'gaussian' % Gaussian filter
siz = (p2-1)/2;
std = p3;
[x,y] = me... |
Google Appengine NDB ancestor vs key query | 17,191,471 | 9 | 2013-06-19T12:41:10Z | 17,192,111 | 11 | 2013-06-19T13:11:04Z | [
"python",
"google-app-engine",
"app-engine-ndb"
] | I am storing a key of an entity as a property of another in order to relate them. We are in a refactor stage at this point in the project so I was thinking about introducing ancestors.
Is there a performance difference between the two approaches? Any given advantages that I might gain if we introduce ancestors?
```
cl... | The ancestor query will always be fully consistent. Querying by `book_key`, on the other hand, will not necessarily be consistent: you may find that recent changes will not be shown in that query.
On the other hand, introducing an ancestor imposes a limit on the number of updates: you can only do one update per second... |
NameError: global name 'xrange' is not defined in Python 3 | 17,192,158 | 54 | 2013-06-19T13:13:04Z | 17,192,181 | 100 | 2013-06-19T13:14:02Z | [
"python",
"python-3.x",
"range",
"runtimeexception",
"xrange"
] | I am getting an error when running a python program:
```
Traceback (most recent call last):
File "C:\Program Files (x86)\Wing IDE 101 4.1\src\debug\tserver\_sandbox.py", line 110, in <module>
File "C:\Program Files (x86)\Wing IDE 101 4.1\src\debug\tserver\_sandbox.py", line 27, in __init__
File "C:\Program Files... | You are trying to run a Python 2 codebase with Python 3. `xrange()` was renamed to `range()` in Python 3.
Run the game with Python 2 instead. Don't try to port it unless you know what you are doing, most likely there will be more problems beyond `xrange()` vs. `range()`.
For the record, what you are seeing is not a s... |
hash function in python | 17,192,418 | 10 | 2013-06-19T13:24:51Z | 17,192,658 | 17 | 2013-06-19T13:34:47Z | [
"python",
"hash",
"sl4a"
] | I believed that `hash()` function works the same in all python interpreters. But it differs when I run it on my mobile using [python for android](https://code.google.com/p/python-for-android/). I get same hash value for hashing strings and numbers but when I hash built-in data types the hash value differs.
**PC Python... | `hash()` is randomised by default each time you start a new instance of recent versions (Python3.3+) to [prevent dictionary insertion DOS attacks](http://mail.python.org/pipermail/python-announce-list/2012-March/009394.html)
Prior to that, `hash()` was different for 32bit and 64bit builds anyway.
If you want somethin... |
How to get column by number in Pandas? | 17,193,850 | 7 | 2013-06-19T14:24:22Z | 17,194,149 | 9 | 2013-06-19T14:37:41Z | [
"python",
"pandas"
] | What's the difference between:
```
Maand['P_Sanyo_Gesloten']
Out[119]:
Time
2012-08-01 00:00:11 0
2012-08-01 00:05:10 0
2012-08-01 00:10:11 0
2012-08-01 00:20:10 0
2012-08-01 00:25:10 0
2012-08-01 00:30:09 0
2012-08-01 00:40:10 0
2012-08-01 00:50:09 0
2012-08-01 01:05:10 0
2012-08-01 01:10:... | One is a column (aka Series), while the other is a DataFrame:
```
In [1]: df = pd.DataFrame([[1,2], [3,4]], columns=['a', 'b'])
In [2]: df
Out[2]:
a b
0 1 2
1 3 4
```
The column 'b' (aka Series):
```
In [3]: df['b']
Out[3]:
0 2
1 4
Name: b, dtype: int64
```
The subdataframe with columns (position) in... |
Is there any way to show the dependency trees for pip packages? | 17,194,301 | 12 | 2013-06-19T14:44:50Z | 24,903,067 | 25 | 2014-07-23T06:10:38Z | [
"python",
"pip",
"requirements",
"requirements.txt"
] | I have a project with multiple package dependencies, the main requirements being listed in `requirements.txt`. When I call `pip freeze` it prints the currently installed packages as plain list. I would prefer to also get their dependency relationships, something like this:
```
Flask==0.9
Jinja2==2.7
Werkzeug==... | You should take a look at [`pipdeptree`](https://pypi.python.org/pypi/pipdeptree/0.3):
```
$ pip install pipdeptree
$ pipdeptree -fl
Warning!!! Cyclic dependencies found:
------------------------------------------------------------------------
xlwt==0.7.5
ruamel.ext.rtf==0.1.1
xlrd==0.9.3
openpyxl==2.0.4
- jdcal==1.... |
Using a variable in a try,catch,finally statement without declaring it outside | 17,195,569 | 14 | 2013-06-19T15:42:21Z | 17,195,686 | 26 | 2013-06-19T15:48:45Z | [
"python",
"scope"
] | I'm pretty new to Python, here is some code I am looking at:
```
try:
connection = getConnection(database)
cursor = connection.cursor()
cursor.execute("some query")
except:
log.error("Problem.")
raise
finally:
cursor.close()
connection.close()
```
Is that being cleaned up properly? In othe... | Python does not have block scope. Anything defined inside the `try` block will be available outside.
That said, you would still have a problem: if it is the `getConnection()` call that raises the error, `cursor` will be undefined, so the reference in the `finally` block will error. |
Python equivalent of unix "strings" utility | 17,195,924 | 6 | 2013-06-19T15:59:56Z | 17,197,027 | 7 | 2013-06-19T16:55:46Z | [
"python",
"string",
"executable"
] | I'm trying to write a script which will extract strings from an executable binary and save them in a file. Having this file be newline-separated isn't an option since the strings could have newlines themselves. This also means, however, that using the unix "strings" utility isn't an option, since it just prints out all... | Here's a generator that yields all the strings of printable characters >= `min` (4 by default) in length that it finds in `filename`:
```
import string
def strings(filename, min=4):
with open(filename, errors="ignore") as f: # Python 3.x
# with open(filename, "rb") as f: # Python 2.x
result... |
Extracting table contents from html with python and BeautifulSoup | 17,196,018 | 3 | 2013-06-19T16:04:56Z | 17,196,799 | 11 | 2013-06-19T16:43:55Z | [
"python",
"beautifulsoup",
"screen-scraping"
] | I want to extract certain information out of an html document. E.g. it contains a table
(among other tables with other contents) like this:
```
<table class="details">
<tr>
<th>Advisory:</th>
<td>RHBA-2013:0947-1</td>
</tr>
<tr>
... | ```
>>> from bs4 import BeautifulSoup
>>> soup = BeautifulSoup(unicodestring_containing_the_entire_htlm_doc)
>>> table = soup.find('table', {'class': 'details'})
>>> th = table.find('th', text='Issued on:')
>>> th
<th>Issued on:</th>
>>> td = th.findNext('td')
>>> td
<td>2013-06-13</td>
>>> td.text
u'2013-06-13'
``` |
Root mean square error in python | 17,197,492 | 24 | 2013-06-19T17:24:10Z | 17,221,808 | 12 | 2013-06-20T19:08:39Z | [
"python",
"scipy"
] | I know I could implement a root mean squared error function like this:
```
def rmse(predictions, targets):
return np.sqrt(((predictions - targets) ** 2).mean())
```
What I'm looking for if this rmse function is implemented in a library somewhere, perhaps in scipy or scikit-learn? | This is probably faster?:
```
n = len(predictions)
rmse = np.linalg.norm(predictions - targets) / np.sqrt(n)
``` |
Root mean square error in python | 17,197,492 | 24 | 2013-06-19T17:24:10Z | 18,623,635 | 35 | 2013-09-04T20:56:57Z | [
"python",
"scipy"
] | I know I could implement a root mean squared error function like this:
```
def rmse(predictions, targets):
return np.sqrt(((predictions - targets) ** 2).mean())
```
What I'm looking for if this rmse function is implemented in a library somewhere, perhaps in scipy or scikit-learn? | `sklearn.metrics` has a `mean_squared_error` function. The RMSE is just the square root of whatever it returns.
```
from sklearn.metrics import mean_squared_error
from math import sqrt
rms = sqrt(mean_squared_error(y_actual, y_predicted))
``` |
Is it possible to overload the multiple comparison syntax in python? | 17,197,953 | 8 | 2013-06-19T17:51:53Z | 17,198,023 | 14 | 2013-06-19T17:54:51Z | [
"python"
] | I'm wondering if it's possible to overload the multiple comparison syntax in python:
```
a < b < c
```
I know it's possible to overload single comparisons, is it possible to overload these? | Internally it is handled as `a < b and b < c`, so you need to overload only `__lt__`, `__gt__`, etc.
From the [docs](http://docs.python.org/2/reference/expressions.html#not-in):
> x < y <= z is equivalent to x < y and y <= z, except that y is
> evaluated only once (but in both cases z is not evaluated at all when
> x... |
2D lists generation Python | 17,198,414 | 2 | 2013-06-19T18:15:13Z | 17,198,447 | 9 | 2013-06-19T18:16:50Z | [
"python",
"list",
"loops"
] | I know that to generate a list in Python you can use something like:
```
l = [i**2 for i in range(5)]
```
instead of using for loop like:
```
l = []
for i in range(5):
l.append(i**5)
```
Is there a way to do 2D lists without using for loops like this:
```
map = [[]]
for x in range(10):
row = []
for y ... | Use a list comprehension here too:
```
>>> [ [(x+y)**2 for y in range(10)] for x in range(10)]
[[0, 1, 4, 9, 16, 25, 36, 49, 64, 81], [1, 4, 9, 16, 25, 36, 49, 64, 81, 100], [4, 9, 16, 25, 36, 49, 64, 81, 100, 121], [9, 16, 25, 36, 49, 64, 81, 100, 121, 144], [16, 25, 36, 49, 64, 81, 100, 121, 144, 169], [25, 36, 49, ... |
None Python error/bug? | 17,198,466 | 15 | 2013-06-19T18:18:38Z | 17,198,511 | 21 | 2013-06-19T18:20:45Z | [
"python",
"python-2.7",
"python-3.x",
"types"
] | In Python you have the `None` singleton, which acts pretty oddly in certain circumstances:
```
>>> a = None
>>> type(a)
<type 'NoneType'>
>>> isinstance(a,None)
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
TypeError: isinstance() arg 2 must be a class, type, or tuple of classes and types
``... | You can try:
```
>>> variable = None
>>> isinstance(variable,type(None))
True
>>> variable = True
>>> isinstance(variable,type(None))
False
```
[isinstance](http://docs.python.org/2/library/functions.html#isinstance) takes 2 arguments `isinstance(object, classinfo)` Here, by passing `None` you are setting `classinfo`... |
None Python error/bug? | 17,198,466 | 15 | 2013-06-19T18:18:38Z | 17,198,512 | 18 | 2013-06-19T18:20:45Z | [
"python",
"python-2.7",
"python-3.x",
"types"
] | In Python you have the `None` singleton, which acts pretty oddly in certain circumstances:
```
>>> a = None
>>> type(a)
<type 'NoneType'>
>>> isinstance(a,None)
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
TypeError: isinstance() arg 2 must be a class, type, or tuple of classes and types
``... | `None` is not a type, it is the singleton instance itself - and the second argument of [`isinstance`](http://docs.python.org/2/library/functions.html#isinstance) must be a type, class or tuple of them. Hence, you need to use `NoneType` from [`types`](http://docs.python.org/2/library/types.html).
```
from types import ... |
psycopg2 leaking memory after large query | 17,199,113 | 10 | 2013-06-19T18:55:55Z | 17,203,872 | 9 | 2013-06-20T01:20:53Z | [
"python",
"postgresql",
"psycopg2"
] | I'm running a large query in a python script against my postgres database using psycopg2 (I upgraded to version 2.5). After the query is finished, I close the cursor and connection, and even run gc, but the process still consumes a ton of memory (7.3gb to be exact). Am I missing a cleanup step?
```
import psycopg2
con... | Please see the *next answer* by @joeblog for the better solution.
---
First, you shouldn't need all that RAM in the first place. What you should be doing here is fetching *chunks* of the result set. Don't do a `fetchall()`. Instead, use the much more efficient `cursor.fetchmany` method. See [the psycopg2 documentatio... |
psycopg2 leaking memory after large query | 17,199,113 | 10 | 2013-06-19T18:55:55Z | 27,940,340 | 19 | 2015-01-14T10:08:11Z | [
"python",
"postgresql",
"psycopg2"
] | I'm running a large query in a python script against my postgres database using psycopg2 (I upgraded to version 2.5). After the query is finished, I close the cursor and connection, and even run gc, but the process still consumes a ton of memory (7.3gb to be exact). Am I missing a cleanup step?
```
import psycopg2
con... | I ran into a similar problem and after a couple of hours of blood, sweat and tears, found the answer simply requires the addition of one parameter.
Instead of
```
cursor = conn.cursor()
```
write
```
cursor = conn.cursor(name="my_cursor_name")
```
or simpler yet
```
cursor = conn.cursor("my_cursor_name")
```
The... |
Scrapy Vs Nutch | 17,199,457 | 11 | 2013-06-19T19:14:32Z | 17,200,157 | 16 | 2013-06-19T19:55:52Z | [
"python",
"solr",
"web-scraping",
"scrapy",
"web-crawler"
] | I am planning to use webcrawling in an application i am currently working on. I did some research on Nutch and run some preliminary test using it. But then i came across scrapy. But when i did some preliminary research and went through the documentation about scrapy i found that it can capture only structed data (You h... | `Scrapy` would work perfectly in your case.
You are not required to give divs names - you can get anything you want:
> Scrapy comes with its own mechanism for extracting data. Theyâre
> called XPath selectors (or just âselectorsâ, for short) because they
> âselectâ certain parts of the HTML document specifi... |
how to use the href attribute in django templates | 17,200,389 | 3 | 2013-06-19T20:11:22Z | 17,200,402 | 9 | 2013-06-19T20:12:10Z | [
"python",
"django",
"url",
"href"
] | When I try to use a link in my Django template from `/appname/index/` to get to `/appname/detail/###` I am instead getting to `/appname/index/detail/###` which is not what I'm trying to get so my app can't find it in the urlconf of course.
First the urls.py line for the detail page
```
url(r'detail/(?P<jobID>\d+)/$',... | Add `/` at start in `href`:
```
<a href="/appname/detail/{{ job.id }}/">{{ job.name }}</a>
```
And for the `url` tag to work you need to do it like this:
```
<a href="{% url 'appname.views.detail' jobID=job.id %}">{{ job.name }}</a>
``` |
A logarithmic colorbar in matplotlib scatter plot | 17,201,172 | 30 | 2013-06-19T20:56:46Z | 17,202,196 | 39 | 2013-06-19T22:06:07Z | [
"python",
"matplotlib"
] | I would like to make the colors of the points on the scatter plot correspond to the value of the void fraction, but on a logarithmic scale to amplify differences. I did this, but now when I do plt.colorbar(), it displays the log of the void fraction, when I really want the actual void fraction. How can I make a log sca... | There is now a section of the documentation describing [how color mapping and normalization works](http://matplotlib.org/devdocs/users/colormapnorms.html) (that is a link to the development documentation, but applies to all versions of mpl. It will be in the mainline documentation 'soon')
The way that `matplotlib` doe... |
Alembic autogenerates empty Flask-SQLAlchemy migrations | 17,201,800 | 8 | 2013-06-19T21:35:54Z | 17,302,718 | 19 | 2013-06-25T16:30:14Z | [
"python",
"sqlalchemy",
"flask",
"flask-sqlalchemy",
"alembic"
] | I'm using Alembic to handle migrations for Flask. `alembic revision --autogenerate` should, in theory, autogenerate a migration based on changes in my database. However, Alembic is simply generating a blank migration with the above command.
There's a [question very similar to this one](http://stackoverflow.com/questio... | Here is how I use Alembic with Flask and blueprints.
<https://github.com/davidism/basic_flask>
I use the application factory pattern and call `db.init_app` within that. After `db = SQLAlchemy()` I import all models that will subclass `db.Model` so that `db.metadata` is aware of them; note this is not done in the `cre... |
Can you search backwards from an offset using a Python regular expression? | 17,203,604 | 8 | 2013-06-20T00:42:12Z | 17,203,696 | 7 | 2013-06-20T00:56:13Z | [
"python",
"regex",
"python-2.7"
] | Given a string, and a character offset within that string, can I search backwards using a Python regular expression?
The actual problem I'm trying to solve is to get a matching phrase at a particular offset within a string, but I have to match the first instance before that offset.
In a situation where I have a regex... | Using positive lookbehind to make sure there are at least 30 characters before a word:
```
# re like: r'.*?(\w+)(?<=.{30})'
m = re.match(r'.*?(\w+)(?<=.{%d})' % (offset), my_string)
if m: print m.group(1)
else: print "no match"
```
For the other example negative lookbehind may help:
```
my_new_string = "Looking feed... |
python ftplib specify port | 17,204,276 | 8 | 2013-06-20T02:15:09Z | 17,204,306 | 10 | 2013-06-20T02:19:13Z | [
"python",
"ftp",
"ftplib"
] | I would like to specify the port with python's ftplib client (instead of default port 21).
Here is the code:
```
from ftplib import FTP
ftp = FTP('localhost') # connect to host, default port
```
Is there an easy way to specify an alternative port? | ```
>>> from ftplib import FTP
>>> HOST = "localhost"
>>> PORT = 12345 # Set your desired port number
>>> ftp = FTP()
>>> ftp.connect(HOST, PORT)
``` |
What is {!text!} in Python? | 17,204,864 | 2 | 2013-06-20T03:39:07Z | 17,204,928 | 8 | 2013-06-20T03:46:23Z | [
"python"
] | What do {!info!} and {!input!} do in this python code?
```
s += " {!info!}Down Speed: {!input!}%s" % common.fspeed(status["download_payload_rate"])
```
Taken from: <http://git.deluge-torrent.org/deluge/tree/deluge/ui/console/commands/info.py?h=1.3-stable>
Thanks. | They don't mean anything to Python. The string `s` will literally contain `{!info!}`and `{!input!}`. However, that string is later interpreted by Deluge itself to do color formatting â see [ui/console/colors.py](http://git.deluge-torrent.org/deluge/tree/deluge/ui/console/colors.py?h=1.3-stable), specifically `parse_c... |
AttributeError: 'NoneType' object has no attribute 'app' | 17,206,728 | 3 | 2013-06-20T06:31:44Z | 17,209,173 | 7 | 2013-06-20T08:48:01Z | [
"python",
"flask",
"xhtml2pdf"
] | The below code gives error:
```
Traceback (most recent call last):
File "pdf.py", line 14, in <module>
create_pdf(render_template('templates.htm'))
File "/usr/local/lib/python2.7/dist-packages/flask/templating.py", line 123, in render_template
ctx.app.update_template_context(context)
AttributeError: 'NoneT... | Flask does a whole lot of 'magic' so you don't have to worry about routing or parsing requests. When a Flask application receives a request, it creates a 'context' object before delegating the logic to your view function.
In your code, you are calling `render_template` directly without going through Flask, so the cont... |
What could be the reason for a socket error "[Errno 9] Bad file descriptor" | 17,207,051 | 5 | 2013-06-20T06:53:23Z | 17,207,158 | 18 | 2013-06-20T06:58:38Z | [
"python",
"sockets",
"python-2.7"
] | I have a complex python (2.7.3) script which is trying to open a socket connection via
```
self.socket.close()
# doing something else
self.socket.connect((host, port))
```
but all I get is the following socket error:
```
error: [Errno 9] Bad file descriptor
```
The `host:port` accepts connections as I have verified... | You will need to create a new socket object. Maybe `self.socket = socket.socket()` after closing the previous socket and before connecting. |
How to find out where a Python Warning is from | 17,208,567 | 8 | 2013-06-20T08:15:00Z | 17,211,698 | 7 | 2013-06-20T10:48:35Z | [
"python",
"debugging",
"warnings",
"pandas"
] | I'm still kinda new with Python, using Pandas, and I've got some issues debugging my Python script.
I've got the following warning message :
```
[...]\pandas\core\index.py:756: UnicodeWarning: Unicode equal comparison failed to convert both arguments to Unicode - interpreting them as being unequal
return self._engine... | You can [filter the warnings](http://docs.python.org/2/library/warnings.html#the-warnings-filter) to raise which will enable you to debug (e.g. using pdb):
```
import warnings
warnings.filterwarnings('error')
```
\*The [warnings filter](http://docs.python.org/2/library/warnings.html#warnings.filterwarnings) can be ma... |
Python: subplot within a loop: first panel appears in wrong position | 17,210,646 | 5 | 2013-06-20T09:54:26Z | 17,211,410 | 11 | 2013-06-20T10:34:34Z | [
"python",
"matplotlib",
"subplot"
] | I am fairly new to Python and come from a more Matlab point of view.
I am trying to make a series of 2 x 5 panel contourf subplots. My approach so far
has been to convert (to a certain degree) my Matlab code to Python and plot my subplots within a loop. The relavent part of the code looks like this:
```
fig=plt.figure... | Using your code with some random data, this would work:
```
fig, axs = plt.subplots(2,5, figsize=(15, 6), facecolor='w', edgecolor='k')
fig.subplots_adjust(hspace = .5, wspace=.001)
axs = axs.ravel()
for i in range(10):
axs[i].contourf(np.random.rand(10,10),5,cmap=plt.cm.Oranges)
axs[i].set_title(str(250+i)... |
pip: upgrade package without upgrading particular dependency | 17,210,896 | 5 | 2013-06-20T10:06:39Z | 27,782,019 | 12 | 2015-01-05T14:53:32Z | [
"python",
"django",
"pip"
] | My question is very much similar to [this](http://stackoverflow.com/questions/2861183/pip-upgrade-package-without-upgrading-dependencies) question. But It differs in a way that if i am installing some package i only want to disable upgrade for a particular dependency not for all dependencies. I know there is a flag `--... | This works and lets you be more precise:
```
pip install -U django-rosetta Django==1.4
``` |
How to temporarily modify sys.path in Python? | 17,211,078 | 10 | 2013-06-20T10:16:01Z | 17,211,123 | 8 | 2013-06-20T10:19:08Z | [
"python",
"python-import"
] | In one of my testing scripts in Python I use this pattern several times:
```
sys.path.insert(0, "somedir")
mod = __import__(mymod)
sys.path.pop(0)
```
Is there a more concise way to temporarily modify the search path? | Appending a value to `sys.path` only modifies it temporarily, i.e for that session only.
Permanent modifications are done by changing `PYTHONPATH` and the default installation directory.
So, if by temporary you meant for current session only then your approach is okay, but you can remove the `pop` part if `somedir` i... |
How to create a timer on python | 17,211,188 | 2 | 2013-06-20T10:22:30Z | 17,211,208 | 10 | 2013-06-20T10:23:46Z | [
"python"
] | I am creating a code that requires the program to time how long it runs for and then displays the time. it is basically a timer that runs in the background and I can call upon it to display how long the code has been running for. How do I do this? | You record the start time, then later on calculate the difference between that start time and the current time.
Due to platform differences, for precision you want to use the [`timeit.default_timer` callable](http://docs.python.org/2/library/timeit.html#timeit.default_timer):
```
from timeit import default_timer
sta... |
How can I consume tweets from Twitter's streaming api and store them in mongodb | 17,213,991 | 18 | 2013-06-20T12:45:27Z | 17,231,813 | 14 | 2013-06-21T09:27:54Z | [
"python",
"mongodb",
"twitter",
"pymongo",
"tweepy"
] | I need to develop an app that lets me track tweets and save them in a mongodb for a research project (as you might gather, I am a noob, so please bear with me). I have found this piece of code that sends tweets streaming through my terminal window:
```
import sys
import tweepy
consumer_key=""
consumer_secret=""
acces... | Here's an example:
```
import json
import pymongo
import tweepy
consumer_key = ""
consumer_secret = ""
access_key = ""
access_secret = ""
auth = tweepy.OAuthHandler(consumer_key, consumer_secret)
auth.set_access_token(access_key, access_secret)
api = tweepy.API(auth)
class CustomStreamListener(tweepy.StreamListene... |
python format string unused named arguments | 17,215,400 | 14 | 2013-06-20T13:50:18Z | 17,215,533 | 34 | 2013-06-20T13:55:49Z | [
"python",
"string",
"string-formatting"
] | Let's say I have:
```
action = '{bond}, {james} {bond}'.format(bond='bond', james='james')
```
this wil output:
```
'bond, james bond'
```
Next we have:
```
action = '{bond}, {james} {bond}'.format(bond='bond')
```
this will output:
```
KeyError: 'james'
```
Is there some workaround to prevent this error to ha... | ## If you are using Python 3.2+, use can use [str.format\_map()](http://docs.python.org/3/library/stdtypes.html#str.format_map).
For `bond, bond`:
```
>>> from collections import defaultdict
>>> '{bond}, {james} {bond}'.format_map(defaultdict(str, bond='bond'))
'bond, bond'
```
For `bond, {james} bond`:
```
>>> cl... |
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