The current best practice (as of this writing in March 2018) is to add a `python_requires` argument directly to the `setup()` call in `setup.py`:


    from setuptools import setup
    
    [...]
    
    setup(name=&quot;my_package_name&quot;,
          python_requires=&#39;&gt;3.5.2&#39;,
          [...]

Note that this requires setuptools&gt;=24.2.0 and pip&gt;=9.0.0; [see the documentation](https://packaging.python.org/guides/distributing-packages-using-setuptools/#python-requires) for more information.

As the `setup.py` file is installed via `pip` (and `pip` itself is run by the python interpreter) it is not possible to specify which Python version to use in the `setup.py` file.

Instead have a look at [this answer](https://stackoverflow.com/a/13925176/1401034) to [setup.py: restrict the allowable version of the python interpreter](https://stackoverflow.com/questions/13924931/setup-py-restrict-the-allowable-version-of-the-python-interpreter) which has a basic workaround to stop the install.

In your case the code would be:

    import sys
    if sys.version_info &lt; (2,7):
        sys.exit(&#39;Sorry, Python &lt; 2.7 is not supported&#39;)

I just noticed that after installing OS X 10.9, the g++ compiler links to the clang compiler. Is there anyway to revert back to gcc/g++?

OS X 10.9 gcc links to clang

We&#39;ve got a requirement in a couple of our systems to detect a user&#39;s country based on their IP address. We&#39;d prefer to use a database rather than a Web Service (to prevent issues with downtime/network access to an externally hosted service) so I&#39;m looking for recommendations, anyone got any good or bad stories of the various IP to Country databases?

What I&#39;ve found from google:

**Paid**

 - [Maxmind][1] - $50, then $12 a month, site license
 - [IP2Location][2] - $50 a year, single server
 - [software77][5] (Donationware)

**Free**

 - [Maxmind Geolite][3]
 - [ip2nation][4]

Any information on how the free ones compare to the paid ones would be good. Right now I&#39;m leaning towards Maxmind&#39;s paid service since it includes automatic updates that we can run via script once a week.

  [1]: http://www.maxmind.com/en/country
  [2]: http://www.ip2location.com/databases/db1-ip-country
  [3]: http://dev.maxmind.com/geoip/legacy/geolite/
  [4]: http://www.ip2nation.com/
  [5]: http://software77.net/geo-ip/

Best IP to Country Database

Currently, we are setting\installing up some packages on system by mentioning their version and dependencies in `setup.py` under `install_requires` attribute. Our system requires Python 2.7. Sometimes, users are having multiple versions of Python on their systems, say 2.6.x and 2.7, some packages it says are available already but actually on the system available under 2.6 site packages list. Also some users have 2.6 only, how to enforce from `setup.py` or is there any other way to say to have only Python 2.7 and all packages which we want `setup.py` to update are for only 2.7. We require minimum 2.7 on the machine to run our code.

Thanks!
Santhosh

Enforcing python version in setup.py

<p>Currently, we are setting\installing up some packages on system by mentioning their version and dependencies in <code>setup.py</code> under <code>install_requires</code> attribute. Our system requires Python 2.7. Sometimes, users are having multiple versions of Python on their systems, say 2.6.x and 2.7, some packages it says are available already but actually on the system available under 2.6 site packages list. Also some users have 2.6 only, how to enforce from <code>setup.py</code> or is there any other way to say to have only Python 2.7 and all packages which we want <code>setup.py</code> to update are for only 2.7. We require minimum 2.7 on the machine to run our code.</p>
<p>Thanks!
Santhosh</p>


I&#39;m working with a module written by someone else. I&#39;d like to monkey patch the `__init__` method of a class defined in the module. The examples I have found showing how to do this have all assumed I&#39;d be calling the class myself (e.g. https://stackoverflow.com/questions/3765222/monkey-patch-python-class). However, this is not the case. In my case the class is initalised within a function in another module. See the (greatly simplified) example below:

**thirdpartymodule_a.py**

    class SomeClass(object):
        def __init__(self):
            self.a = 42
        def show(self):
            print self.a

**thirdpartymodule_b.py**

    import thirdpartymodule_a
    def dosomething():
        sc = thirdpartymodule_a.SomeClass()
        sc.show()

**mymodule.py**

    import thirdpartymodule_b
    thirdpartymodule_b.dosomething()

Is there any way to modify the `__init__` method of `SomeClass` so that when `dosomething` is called from mymodule.py it, for example, prints 43 instead of 42? Ideally I&#39;d be able to wrap the existing method.

I can&#39;t change the thirdpartymodule*.py files, as other scripts depend on the existing functionality. I&#39;d rather not have to create my own copy of the module, as the change I need to make is very simple.

**Edit 2013-10-24**

I overlooked a small but important detail in the example above. `SomeClass` is imported by `thirdpartymodule_b` like this: `from thirdpartymodule_a import SomeClass`.

To do the patch suggested by F.J I need to replace the copy in `thirdpartymodule_b`, rather than `thirdpartymodule_a`. e.g. `thirdpartymodule_b.SomeClass.__init__ = new_init`.

Monkey patching a class in another module in Python

I want to install Lxml so I can then install Scrapy.

When I updated my Mac today it wouldn&#39;t let me reinstall lxml, I get the following error:

    

    In file included from src/lxml/lxml.etree.c:314:
    /private/tmp/pip_build_root/lxml/src/lxml/includes/etree_defs.h:9:10: fatal error: &#39;libxml/xmlversion.h&#39; file not found
    #include &quot;libxml/xmlversion.h&quot;
             ^
    1 error generated.
    error: command &#39;cc&#39; failed with exit status 1

I have tried using brew to install libxml2 and libxslt, both installed fine but I still cannot install lxml.

Last time I was installing I needed to enable the developer tools on Xcode but since it&#39;s updated to Xcode 5 it doesn&#39;t give me that option anymore.

Does anyone know what I need to do?

Cannot install Lxml on Mac OS X 10.9

I&#39;ve come across situations where a current version of a package seems not to be working and requires reinstallation. But `pip install -U` won&#39;t touch a package that is already up-to-date. I see how to force a reinstallation by first uninstalling (with `pip uninstall`) and then installing, but is there a way to simply force an &quot;update&quot; to a nominally current version in a single step?

Can I force pip to reinstall the current version?

I&#39;m using pandas to generate a plot from a dataframe, which I would like to save to a file:


    dtf = pd.DataFrame.from_records(d,columns=h)
    fig = plt.figure()
    ax = dtf2.plot()
    ax = fig.add_subplot(ax)
    fig.savefig(&#39;~/Documents/output.png&#39;)

It seems like the last line, using matplotlib&#39;s savefig, should do the trick.  But that code produces the following error:

    Traceback (most recent call last):
      File &quot;./testgraph.py&quot;, line 76, in &lt;module&gt;
        ax = fig.add_subplot(ax)
      File &quot;/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/matplotlib/figure.py&quot;, line 890, in add_subplot
        assert(a.get_figure() is self)
    AssertionError


Alternatively, trying to call savefig directly on the plot also errors out:

    dtf2.plot().savefig(&#39;~/Documents/output.png&#39;)


      File &quot;./testgraph.py&quot;, line 79, in &lt;module&gt;
        dtf2.plot().savefig(&#39;~/Documents/output.png&#39;)
    AttributeError: &#39;AxesSubplot&#39; object has no attribute &#39;savefig&#39;


I think I need to somehow add the subplot returned by plot() to a figure in order to use savefig.  I also wonder if perhaps this has to do with the [magic](https://stackoverflow.com/questions/11690597/there-is-a-class-matplotlib-axes-axessubplot-but-the-module-matplotlib-axes-has) behind the AxesSubPlot class.


EDIT: 

the following works (raising no error), but leaves me with a blank page image....

    fig = plt.figure()
    dtf2.plot()
    fig.savefig(&#39;output.png&#39;)

EDIT 2:
The below code works fine as well
```
dtf2.plot().get_figure().savefig(&#39;output.png&#39;)
```



Saving plots (AxesSubPlot) generated from python pandas with matplotlib&#39;s savefig

Is there a way to print the number of raw SQL queries performed by the Django ORM during a Django shell session?

This sort of information is already provided by the Django debug toolbar (e.g, `5 QUERIES in 5.83MS` but it&#39;s not obvious how to get it from the shell.

Get SQL query count during a Django shell session

I&#39;m having problems reading from a file, processing its string and saving to an UTF-8 File.

Here is the code:

    try:
        filehandle = open(filename,&quot;r&quot;)
    except:
        print(&quot;Could not open file &quot; + filename)
        quit() 
    
    text = filehandle.read()
    filehandle.close()

I then do some processing on the variable text.

And then 

    try:
        writer = open(output,&quot;w&quot;)
    except:
        print(&quot;Could not open file &quot; + output)
        quit() 
        
    #data = text.decode(&quot;iso 8859-15&quot;)    
    #writer.write(data.encode(&quot;UTF-8&quot;))
    writer.write(text)
    writer.close()

This output the file perfectly but it does so in iso 8859-15 according to my editor. Since the same editor recognizes the input file (in the variable filename) as UTF-8 I don&#39;t know why this happened. As far as my reasearch has shown the commented lines should solve the problem. However when I use those lines the resulting file has gibberish in special character mainly, words with tilde as the text is in spanish. I would really appreciate any help as I am stumped....

Python reading from a file and saving to utf-8

I&#39;m trying to run a macro via python but I&#39;m not sure how to get it working...

I&#39;ve got the following code so far, but it&#39;s not working.

    import win32com.client
    xl=win32com.client.Dispatch(&quot;Excel.Application&quot;)
    xl.Workbooks.Open(Filename=&quot;C:\test.xlsm&quot;,ReadOnly=1)
    xl.Application.Run(&quot;macrohere&quot;)
    xl.Workbooks(1).Close(SaveChanges=0)
    xl.Application.Quit()
    xl=0

I get the following traceback:

    Traceback (most recent call last):
      File &quot;C:\test.py&quot;, line 4, in &lt;module&gt;
        xl.Application.Run(&quot;macrohere&quot;)
      File &quot;&lt;COMObject &lt;unknown&gt;&gt;&quot;, line 14, in Run
      File &quot;C:\Python27\lib\site-packages\win32com\client\dynamic.py&quot;, line 282, in _ApplyTypes_
        result = self._oleobj_.InvokeTypes(*(dispid, LCID, wFlags, retType, argTypes) + args)
    com_error: (-2147352567, &#39;Exception occurred.&#39;, (0, u&#39;Microsoft Excel&#39;, u&quot;Cannot run the macro &#39;macrohere&#39;. The macro may not be available in this workbook or all macros may be disabled.&quot;, u&#39;xlmain11.chm&#39;, 0, -2146827284), None)

### EDIT

    import win32com.client
    xl=win32com.client.Dispatch(&quot;Excel.Application&quot;)
    xl.Workbooks.Open(Filename=&quot;C:\test.xlsm&quot;,ReadOnly=1)
    try:
        xl.Application.Run(&quot;test.xlsm!testmacro.testmacro&quot;)
        # It does run like this... but we get the following error:
        # Traceback (most recent call last):
            # File &quot;C:\test.py&quot;, line 7, in &lt;module&gt;
            # xl.Workbooks(1).Close(SaveChanges=0)
            # File &quot;C:\Python27\lib\site-packages\win32com\client\dynamic.py&quot;, line 192, in __call__
            # return self._get_good_object_(self._oleobj_.Invoke(*allArgs),self._olerepr_.defaultDispatchName,None)
        # com_error: (-2147352567, &#39;Exception occurred.&#39;, (0, None, None, None, 0, -2147352565), None)
    except:
        # Except isn&#39;t catching the above error... :(
        xl.Workbooks(1).Close(SaveChanges=0)
        xl.Application.Quit()
        xl=0



Running an Excel macro via Python?

Why python 2.7 doesn&#39;t include Z character (Zulu or zero offset) at the end of UTC datetime object&#39;s isoformat string unlike JavaScript?

    &gt;&gt;&gt; datetime.datetime.utcnow().isoformat()
    &#39;2013-10-29T09:14:03.895210&#39;

Whereas in javascript

    &gt;&gt;&gt;  console.log(new Date().toISOString()); 
    2013-10-29T09:38:41.341Z


Python UTC datetime object&#39;s ISO format doesn&#39;t include Z (Zulu or Zero offset)

Using `pip install zipline` on Windows 8 with Python 2.7 gives me the error:

	Downloading/unpacking six (from python-dateutil==2.1-&gt;delorean-&gt;zipline[all])
	  Running setup.py egg_info for package six

	Installing collected packages: blist, pytz, requests, python-dateutil, six
	  Running setup.py install for blist
	    building &#39;_blist&#39; extension
	    error: Unable to find vcvarsall.bat
	    Complete output from command C:\Python27\python.exe -c &quot;import setuptools;__
	file__=&#39;c:\\users\\ThatsMe\\appdata\\local\\temp\\pip-build-ThatsMe\\blist\\setup.py&#39;;ex
	ec(compile(open(__file__).read().replace(&#39;\r\n&#39;, &#39;\n&#39;), __file__, &#39;exec&#39;))&quot; inst
	all --record c:\users\ThatsMe\appdata\local\temp\pip-xvoky2-record\install-record.tx
	t --single-version-externally-managed:

    running install

    running build

    running build_py

    running build_ext

    building &#39;_blist&#39; extension

    error: Unable to find vcvarsall.bat

**Question:** How can the error be resolved? Running `pip install zipline[all]` gives the same error...

pip install gives error: Unable to find vcvarsall.bat

If I do something with list comprehensions, it writes to a local variable:

    i = 0
    test = any([i == 2 for i in xrange(10)])
    print i

This prints &quot;9&quot;. However, if I use a generator, it doesn&#39;t write to a local variable:

    i = 0
    test = any(i == 2 for i in xrange(10))
    print i

This prints &quot;0&quot;.

Is there any good reason for this difference? Is this a design decision, or just a random byproduct of the way that generators and list comprehensions are implemented? Personally, it would seem better to me if list comprehensions didn&#39;t write to local variables.

Why do list comprehensions write to the loop variable, but generators don&#39;t?

Is it possible to specify a post-install Python script file as part of the setuptools setup.py file so that a user can run the command:
    
    python setup.py install

on a local project file archive, or

    pip install &lt;name&gt;

for a PyPI project and the script will be run at the completion of the standard setuptools install?  I am looking to perform post-install tasks that can be coded in a single Python script file (e.g. deliver a custom post-install message to the user, pull additional data files from a different remote source repository).

I came across [this SO answer from several years ago][1] that addresses the topic and it sounds as though the consensus at that time was that you need to create an install subcommand.  If that is still the case, would it be possible for someone to provide an example of how to do this so that it is not necessary for the user to enter a second command to run the script?


  [1]: https://stackoverflow.com/questions/250038/how-can-i-add-post-install-scripts-to-easy-install-setuptools-distutils

Post-install script with Python setuptools

Using the recent (1.5) version of `pip`, I get an error when attempting to update several packages. For example, `sudo pip install -U pytz` results in failure with:

    Wheel installs require setuptools &gt;= 0.8 for dist-info support.
    pip&#39;s wheel support requires setuptools &gt;= 0.8 for dist-info support.

I don&#39;t understand this message [(I have `setuptools` 2.1)][1] or what to do about it.

---

Exception information from the log for this error:

    Exception information:
    Traceback (most recent call last):
      File &quot;/Library/Python/2.7/site-packages/pip/basecommand.py&quot;, line 122, in main
        status = self.run(options, args)
      File &quot;/Library/Python/2.7/site-packages/pip/commands/install.py&quot;, line 230, in run
        finder = self._build_package_finder(options, index_urls, session)
      File &quot;/Library/Python/2.7/site-packages/pip/commands/install.py&quot;, line 185, in _build_package_finder
        session=session,
      File &quot;/Library/Python/2.7/site-packages/pip/index.py&quot;, line 50, in __init__
        self.use_wheel = use_wheel
      File &quot;/Library/Python/2.7/site-packages/pip/index.py&quot;, line 89, in use_wheel
        raise InstallationError(&quot;pip&#39;s wheel support requires setuptools &gt;= 0.8 for dist-info support.&quot;)
    InstallationError: pip&#39;s wheel support requires setuptools &gt;= 0.8 for dist-info support.


  [1]: https://stackoverflow.com/q/21063614/656912

Latest &#39;pip&#39; fails with &quot;requires setuptools &gt;= 0.8 for dist-info&quot;

I have a module that works both on python 2 and python 3. In Python&lt;3.2 I would like to install a specific package as a dependency. For Python&gt;=3.2.

Something like:

     install_requires=[
        &quot;threadpool &gt;= 1.2.7 if python_version &lt; 3.2.0&quot;,
     ],

How can one make that?

install_requires based on python version

The &quot;Python Distribute&quot; guide (was at python-distribute.org, but that registration has lapsed) tells me to include `doc/txt` files and `.py` files are excluded in `MANIFEST.in` file

The [sourcedist documentation](https://docs.python.org/2/distutils/sourcedist.html#manifest-template) tells me only sdist uses `MANIFEST.in` and only includes file you specify and to include `.py` files. It also tells me to use: `python setup.py sdist --manifest-only` to generate a `MANIFEST`, but python tells me this doesn&#39;t exist


I appreciate these are from different versions of python and the distribution system is in a
complete mess, but assuming I am using python 3 and `setuptools` (the new one that includes distribute but now called setuptools, not the old setuptools that was deprecated for distribute tools only to be brought back into distribute and distribute renamed to setuptools.....)

and I&#39;m following the &#39;standard&#39; folder structure and `setup.py` file, 

 1. Do I need a `MANIFEST.in` ?
 2. What should be in it ?
 3. When will all these different package systems and methods be made into one single simple process ?

Do python projects need a MANIFEST.in, and what should be in it?

Python has a confusing history of tools that can be used to package and describe projects: these include `distutils` in the Standard Library, `distribute`, `distutils2`, and `setuptools` (and maybe more). It appears that `distribute` and `distutils2` were discontinued in favor of `setuptools`, which leaves two competing standards.

To my understanding `setuptools` offers far more options (e.g. declaring dependencies, tests, etc.) than `distutils`, however it is not included in the Python standard library (yet?).

The *Python Packaging User Guide*[[1]] recommends now:

&gt; Use `setuptools` to define projects and create Source Distributions.

And explains:

&gt; Although you can use pure `distutils` for many projects, it does not support defining dependencies      on other projects and is missing several convenience utilities for automatically populating package  metadata correctly that are provided by `setuptools`. Being outside the standard library, setuptools  also offers a more consistent feature set across different versions of Python, and (unlike `distutils`), `setuptools` will be updated to produce the upcoming “Metadata 2.0” standard formats on all supported versions.
&gt;
&gt;Even for projects that do choose to use `distutils`, when pip installs such projects directly from source (rather than installing from a prebuilt wheel file), it will actually build your project using `setuptools` instead.

However, looking into various project&#39;s *setup.py* files reveals that this does not seem to be an actual standard. Many packages still use `distutils` and those that support `setuptools` often mix `setuptools` with `distutils` e.g. by doing a fallback import:

    try:
        from setuptools import setup
    except ImportError:
        from distutils.core import setup

Followed by an attempt to find a way to write a setup that can be installed by both `setuptools` and `distutils`. This often includes various ways of error-prone dependency checking, since `distutils` does not support dependencies in the setup function.

Why are people still making the extra effort to support `distutils` - is the fact that `setuptools` is not in the standard library the only reason? What are the advantages of `distutils` and are there any drawbacks of writing *setup.py* files that only support `setuptools`. 

[1]:https://packaging.python.org/guides/tool-recommendations/

Content Type	Original Author	Original Content on Stackoverflow
Question	Santhosh	View Question on Stackoverflow
Solution 1 - Python	Aaron V	View Answer on Stackoverflow
Solution 2 - Python	Ewan	View Answer on Stackoverflow

Enforcing python version in setup.py

Python Problem Overview

Python Solutions

Solution 1 - Python

Solution 2 - Python

Best IP to Country Database

OS X 10.9 gcc links to clang

Attributions