Python 3.2

https://docs.python.org/3.2
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### Setup file example: foo module

Source: https://docs.python.org/3.2/install/index.html

Example Setup file line defining a module named 'foo' built from 'foomodule.c'.

```text
foo foomodule.c
```

--------------------------------

### setup() with requires, obsoletes, and download_url

Source: https://docs.python.org/3.2/whatsnew/2.5.html

Example of using the new setup() keyword parameters from PEP 314 to declare dependencies and a download URL. The requires parameter lists dependencies with optional version constraints, obsoletes lists packages this one replaces, and download_url points to the source archive. Note the missing comma after obsoletes in the original example.

```python
VERSION = '1.0'
setup(name='PyPackage',
      version=VERSION,
      requires=['numarray', 'zlib (>=1.1.4)'],
      obsoletes=['OldPackage']
      download_url=('http://www.example.com/pypackage/dist/pkg-%s.tar.gz'
                    % VERSION),
     )
```

--------------------------------

### Distutils setup script with metadata and packages

Source: https://docs.python.org/3.2/distutils/setupscript.html

Example setup script for a package distribution, showing metadata and the packages argument. Pathnames should use Unix conventions.

```python
#!/usr/bin/env python

from distutils.core import setup

setup(name='Distutils',
      version='1.0',
      description='Python Distribution Utilities',
      author='Greg Ward',
      author_email='gward@python.net',
      url='http://www.python.org/sigs/distutils-sig/',
      packages=['distutils', 'distutils.command'],
     )
```

--------------------------------

### Example INI configuration file

Source: https://docs.python.org/3.2/library/configparser.html

A basic INI configuration file with a DEFAULT section and two other sections. It is used as the example for the quick start guide.

```ini
[DEFAULT]
ServerAliveInterval = 45
Compression = yes
CompressionLevel = 9
ForwardX11 = yes

[bitbucket.org]
User = hg

[topsecret.server.com]
Port = 50022
ForwardX11 = no
```

--------------------------------

### setup.py for a C extension (PyXML example)

Source: https://docs.python.org/3.2/whatsnew/2.0.html

An example setup.py for a C extension, taken from the PyXML package. It defines an Extension object with macros, include directories, and source files, then passes it to setup() via ext_modules.

```python
from distutils.core import setup, Extension

expat_extension = Extension('xml.parsers.pyexpat',
     define_macros = [('XML_NS', None)],
     include_dirs = [ 'extensions/expat/xmltok',
                      'extensions/expat/xmlparse' ],
     sources = [ 'extensions/pyexpat.c',
                 'extensions/expat/xmltok/xmltok.c',
                 'extensions/expat/xmltok/xmlrole.c', ]
       )
setup (name = "PyXML", version = "0.5.4",
       ext_modules =[ expat_extension ] )

```

--------------------------------

### Setup file example: linking math library

Source: https://docs.python.org/3.2/install/index.html

Shows how to add the -lm flag to link the math library libm.a for the 'foo' module.

```text
foo foomodule.c -lm
```

--------------------------------

### Install a Python module on Windows

Source: https://docs.python.org/3.2/install/index.html

Run this command from a command prompt window (Start ‣ Accessories) to install a module distribution on Windows. This is the Windows equivalent of 'python setup.py install'.

```bash
setup.py install
```

--------------------------------

### Setup file example: custom compiler and linker flags

Source: https://docs.python.org/3.2/install/index.html

Demonstrates using -Xcompiler and -Xlinker options to pass arbitrary switches to the compiler and linker.

```text
foo foomodule.c -Xcompiler -o32 -Xlinker -shared -lm
```

--------------------------------

### Specify data_files in setup()

Source: https://docs.python.org/3.2/distutils/setupscript.html

Shows how to pass the data_files option to setup() as a sequence of (directory, files) pairs. The directory can be relative to the installation prefix or absolute, and file names are relative to the setup.py script. An empty string directory installs files directly in the target directory.

```python
setup(...,
      data_files=[('bitmaps', ['bm/b1.gif', 'bm/b2.gif']),
                  ('config', ['cfg/data.cfg']),
                  ('/etc/init.d', ['init-script'])]
     )
```

--------------------------------

### Run a module with -m (timeit example)

Source: https://docs.python.org/3.2/using/cmdline.html

Shows how to use the -m option to run a module as a script, using the timeit module as an example. The first command runs a benchmark with setup code, and the second displays help for timeit.

```bash
python -mtimeit -s 'setup here' 'benchmarked code here'
python -mtimeit -h # for details
```

--------------------------------

### Install Python 2.5.1 on OpenBSD i386 using pkg_add

Source: https://docs.python.org/3.2/using/unix.html

Example command for i386 users to install Python 2.5.1 on OpenBSD.

```shell
pkg_add ftp://ftp.openbsd.org/pub/OpenBSD/4.2/packages/i386/python-2.5.1p2.tgz
```

--------------------------------

### Start a BaseManager server with serve_forever()

Source: https://docs.python.org/3.2/library/multiprocessing.html

Example showing how to create a BaseManager, get its server, and call serve_forever() to start the manager server. The address and authkey are specified.

```python
>>> from multiprocessing.managers import BaseManager
>>> manager = BaseManager(address=('', 50000), authkey=b'abc')
>>> server = manager.get_server()
>>> server.serve_forever()
```

--------------------------------

### enumerate() usage examples

Source: https://docs.python.org/3.2/library/functions.html

Shows how to use enumerate() with and without the start parameter. The first example returns tuples with counts starting at 0, the second starts at 1.

```python
>>> seasons = ['Spring', 'Summer', 'Fall', 'Winter']
>>> list(enumerate(seasons))
[(0, 'Spring'), (1, 'Summer'), (2, 'Fall'), (3, 'Winter')]
>>> list(enumerate(seasons, start=1))
[(1, 'Spring'), (2, 'Summer'), (3, 'Fall'), (4, 'Winter')]
```

--------------------------------

### python setup.py --help build_ext output

Source: https://docs.python.org/3.2/distutils/configfile.html

Output of the universal --help option for the build_ext command, listing supported options such as --build-lib, --build-temp, --inplace, --include-dirs, --define, --undef, and --swig-opts.

```text
> python setup.py --help build_ext
[...]
Options for 'build_ext' command:
  --build-lib (-b)     directory for compiled extension modules
  --build-temp (-t)    directory for temporary files (build by-products)
  --inplace (-i)       ignore build-lib and put compiled extensions into the
                       source directory alongside your pure Python modules
  --include-dirs (-I)  list of directories to search for header files
  --define (-D)        C preprocessor macros to define
  --undef (-U)         C preprocessor macros to undefine
  --swig-opts          list of SWIG command line options
[...]
```

--------------------------------

### Get linker flags with python3.2-config --ldflags

Source: https://docs.python.org/3.2/extending/embedding.html

Run the pythonX.Y-config script with the --ldflags option to obtain recommended linker flags for embedding Python. The example uses the absolute path /opt/bin/python3.2-config to avoid confusion between multiple Python installations.

```bash
$ /opt/bin/python3.2-config --ldflags
-I/opt/lib/python3.2/config-3.2m -lpthread -ldl -lutil -lm -lpython3.2m -Xlinker -export-dynamic
```

--------------------------------

### Get compiler flags with python3.2-config --cflags

Source: https://docs.python.org/3.2/extending/embedding.html

Run the pythonX.Y-config script with the --cflags option to obtain recommended compiler flags for embedding Python. The example uses the absolute path /opt/bin/python3.2-config to avoid confusion between multiple Python installations.

```bash
$ /opt/bin/python3.2-config --cflags
-I/opt/include/python3.2m -I/opt/include/python3.2m -DNDEBUG -g -fwrapv -O3 -Wall -Wstrict-prototypes
```

--------------------------------

### Basic setup.py for a simple extension

Source: https://docs.python.org/3.2/extending/building.html

A minimal setup.py that defines an extension module named 'demo' from a single source file demo.c. Running 'python setup.py build' compiles the extension and produces a module file like demo.so or demo.pyd in the build directory.

```python
from distutils.core import setup, Extension

module1 = Extension('demo',
                    sources = ['demo.c'])

setup (name = 'PackageName',
       version = '1.0',
       description = 'This is a demo package',
       ext_modules = [module1])
```

--------------------------------

### GET Request Example

Source: https://docs.python.org/3.2/library/http.client.html

Demonstrates sending a GET request using http.client.HTTPConnection and reading the response.

```APIDOC
## GET Request Example

### Description
Demonstrates sending a GET request using http.client.HTTPConnection and reading the response.

### Method
GET

### Endpoint
/index.html

### Parameters
#### Path Parameters
- None

#### Query Parameters
- None

#### Request Body
- None

### Request Example
```python
import http.client
conn = http.client.HTTPConnection("www.python.org")
conn.request("GET", "/index.html")
r1 = conn.getresponse()
print(r1.status, r1.reason)
data1 = r1.read()
conn.close()
```

### Response
#### Success Response (200)
- **status** (int) - HTTP status code
- **reason** (string) - Reason phrase
- **data** (bytes) - Response body

#### Response Example
```
200 OK
b'<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"...'
```

### Error Response (404)
- **status** (int) - HTTP status code
- **reason** (string) - Reason phrase
- **data** (bytes) - Response body

#### Error Response Example
```
404 Not Found
```
```

--------------------------------

### Setup file line structure

Source: https://docs.python.org/3.2/install/index.html

Shows the general structure of a line in a Setup file, which describes a single module to build.

```text
module ... [sourcefile ...] [cpparg ...] [library ...]
```

--------------------------------

### Set and get turtle shape with turtle.shape()

Source: https://docs.python.org/3.2/library/turtle.html

Set the turtle shape to a named shape or get the current shape name. The example shows getting the default 'classic' and setting to 'turtle'.

```python
>>> turtle.shape()
'classic'
>>> turtle.shape("turtle")
>>> turtle.shape()
'turtle'
```

--------------------------------

### List available distribution formats with python setup.py bdist --help-formats

Source: https://docs.python.org/3.2/distutils/introduction.html

Displays the distribution formats available at any time for the bdist command.

```bash
python setup.py bdist --help-formats
```

--------------------------------

### turtle.setup(width, height, startx, starty)

Source: https://docs.python.org/3.2/library/turtle.html

Sets the size and position of the main window. Default values are stored in the configuration dictionary and can be changed via a turtle.cfg file.

```APIDOC
## turtle.setup(width, height, startx, starty)

### Description
Set the size and position of the main window. Default values of arguments are stored in the configuration dictionary and can be changed via a turtle.cfg file.

### Method
setup()

### Parameters
- **width** (int or float) - Optional - If an integer, a size in pixels; if a float, a fraction of the screen; default is 50% of screen.
- **height** (int or float) - Optional - If an integer, the height in pixels; if a float, a fraction of the screen; default is 75% of screen.
- **startx** (int or None) - Optional - If positive, starting position in pixels from the left edge of the screen; if negative from the right edge; if None, center window horizontally.
- **starty** (int or None) - Optional - If positive, starting position in pixels from the top edge of the screen; if negative from the bottom edge; if None, center window vertically.

### Request Example
```python
>>> screen.setup (width=200, height=200, startx=0, starty=0)
>>>              # sets window to 200x200 pixels, in upper left of screen
>>> screen.setup(width=.75, height=0.5, startx=None, starty=None)
>>>              # sets window to 75% of screen by 50% of screen and centers
```

### Response
None
```

--------------------------------

### pkgutil.get_data example

Source: https://docs.python.org/3.2/whatsnew/2.6.html

Example usage of pkgutil.get_data() to retrieve the contents of a resource file included with an installed Python package. The output shows the hierarchy of exception classes.

```python
>>> import pkgutil
>>> print pkgutil.get_data('test', 'exception_hierarchy.txt')
BaseException
 +-- SystemExit
 +-- KeyboardInterrupt
 +-- GeneratorExit
 +-- Exception
      +-- StopIteration
      +-- StandardError
 ...
```

--------------------------------

### setup.py for a distribution with packages

Source: https://docs.python.org/3.2/whatsnew/2.0.html

A setup.py script for software consisting of a few packages. It uses the packages parameter to list the package names, including subpackages.

```python
from distutils.core import setup
setup (name = "foo", version = "1.0",
       packages = ["package", "package.subpackage"])

```

--------------------------------

### doctest: Starting column doesn't matter

Source: https://docs.python.org/3.2/library/doctest.html

Shows that the starting column of a doctest example is irrelevant. Leading whitespace is stripped from expected output based on the initial '>>> ' line.

```python
>>> assert "Easy!"
      >>> import math
          >>> math.floor(1.9)
          1
```

--------------------------------

### Run example.py from command line

Source: https://docs.python.org/3.2/library/doctest.html

Command to run the example module directly. No output indicates all doctest examples passed.

```shell
$ python example.py
$
```

--------------------------------

### Query match object with group(), start(), end(), span()

Source: https://docs.python.org/3.2/howto/regex.html

Demonstrates how to use the match object methods to get the matched string, start and end positions, and a tuple of both.

```python
>>> m.group()
'tempo'
>>> m.start(), m.end()
(0, 5)
>>> m.span()
(0, 5)
```

--------------------------------

### Build and install separately

Source: https://docs.python.org/3.2/install/index.html

Builds everything in one step, then installs in a second step. Running install first runs build, which notices nothing to do if build is up-to-date.

```bash
python setup.py build
python setup.py install
```

--------------------------------

### Create Windows executable installer with python setup.py bdist_wininst

Source: https://docs.python.org/3.2/distutils/introduction.html

Creates an executable installer for Windows users. The resulting file is foo-1.0.win32.exe in the current directory.

```bash
python setup.py bdist_wininst
```

--------------------------------

### Output of the example HTML parser

Source: https://docs.python.org/3.2/library/html.parser.html

The expected output when running the example parser. It shows the sequence of start tags, end tags, and data encountered while parsing the HTML string.

```text
Encountered a start tag: html
Encountered a start tag: head
Encountered a start tag: title
Encountered some data  : Test
Encountered an end tag : title
Encountered an end tag : head
Encountered a start tag: body
Encountered a start tag: h1
Encountered some data  : Parse me!
Encountered an end tag : h1
Encountered an end tag : body
Encountered an end tag : html
```

--------------------------------

### NNTP.stat() example

Source: https://docs.python.org/3.2/library/nntplib.html

Shows how to use the stat() method to get the article number and message id for the first article in a group. The example prints the returned number and message id.

```python
>>> _, _, first, last, _ = s.group('gmane.comp.python.devel')
>>> resp, number, message_id = s.stat(first)
>>> number, message_id
(9099, '<20030112190404.GE29873@epoch.metaslash.com>')
```

--------------------------------

### setup.py with classifiers for Distutils

Source: https://docs.python.org/3.2/whatsnew/2.3.html

Example setup.py that uses the classifiers keyword if supported, falling back gracefully for older Distutils versions. The full list of classifiers can be obtained with 'python setup.py register --list-classifiers'.

```python
from distutils import core
kw = {'name': "Quixote",
      'version': "0.5.1",
      'description': "A highly Pythonic Web application framework",
      # ...
      }

if (hasattr(core, 'setup_keywords') and
    'classifiers' in core.setup_keywords):
    kw['classifiers'] = \
        ['Topic :: Internet :: WWW/HTTP :: Dynamic Content',
         'Environment :: No Input/Output (Daemon)',
         'Intended Audience :: Developers'],

core.setup(**kw)
```

--------------------------------

### distutils.core.run_setup

Source: https://docs.python.org/3.2/distutils/apiref.html

Runs a setup script in a controlled environment and returns the Distribution instance. Useful for retrieving distribution metadata, config file contents, or command-line data.

```APIDOC
## distutils.core.run_setup

### Description
Runs a setup script in a somewhat controlled environment, and returns the distutils.dist.Distribution instance that drives things. This is useful if you need to find out the distribution meta-data (passed as keyword args from the script to setup()), or the contents of the config files or command-line.

### Parameters
- **script_name** (str) - Required - A file that will be read and run with exec(). sys.argv[0] will be replaced with script for the duration of the call.
- **script_args** (list of str) - Optional - If supplied, sys.argv[1:] will be replaced by script_args for the duration of the call.
- **stop_after** (str) - Optional - Tells setup() when to stop processing. Possible values: 'init', 'config', 'commandline', 'run'. Default is 'run'.

### Return Value
Returns the distutils.dist.Distribution instance that drives the setup process.

### Notes
- The stop_after values have the following meanings:
  - 'init': Stop after the Distribution instance has been created and populated with the keyword arguments to setup().
  - 'config': Stop after config files have been parsed (and their data stored in the Distribution instance).
  - 'commandline': Stop after the command-line (sys.argv[1:] or script_args) have been parsed (and the data stored in the Distribution instance).
  - 'run': Stop after all commands have been run (the same as if setup() had been called in the usual way). This is the default value.
```

--------------------------------

### Output of the xml.parsers.expat example program

Source: https://docs.python.org/3.2/library/pyexpat.html

This is the output produced by the example program. It shows the sequence of handler calls: start elements with attributes, character data (including newlines), and end elements.

```text
Start element: parent {'id': 'top'}
Start element: child1 {'name': 'paul'}
Character data: 'Text goes here'
End element: child1
Character data: '\n'
Start element: child2 {'name': 'fred'}
Character data: 'More text'
End element: child2
Character data: '\n'
End element: parent
```

--------------------------------

### Set up qsort and integer array for callback example

Source: https://docs.python.org/3.2/library/ctypes.html

Creates an array of 5 integers and configures the qsort function from the C library to have no return value. This is the initial setup for the callback example.

```python
>>> IntArray5 = c_int * 5
>>> ia = IntArray5(5, 1, 7, 33, 99)
>>> qsort = libc.qsort
>>> qsort.restype = None
>>>
```

--------------------------------

### Setup script with one extension

Source: https://docs.python.org/3.2/distutils/setupscript.html

Complete setup script for a distribution containing only the 'foo' extension. Imports setup and Extension from distutils.core.

```python
from distutils.core import setup, Extension
setup(name='foo',
      version='1.0',
      ext_modules=[Extension('foo', ['foo.c'])],
      )
```

--------------------------------

### Run example.py with -v flag

Source: https://docs.python.org/3.2/library/doctest.html

Command to run the example module with verbose output. Shows detailed log of each test and a summary at the end.

```shell
$ python example.py -v
Trying:
    factorial(5)
Expecting:
    120
ok
Trying:
    [factorial(n) for n in range(6)]
Expecting:
    [1, 1, 2, 6, 24, 120]
ok
```

--------------------------------

### Get the screen with getscreen() and change background

Source: https://docs.python.org/3.2/library/turtle.html

Returns the TurtleScreen object the turtle is drawing on, allowing TurtleScreen methods to be called. The example shows getting the screen and setting its background color.

```python
>>> ts = turtle.getscreen()
>>> ts
<turtle._Screen object at 0x...>
>>> ts.bgcolor("pink")
```

--------------------------------

### Basic setup.cfg syntax

Source: https://docs.python.org/3.2/distutils/configfile.html

Shows the general structure of a Distutils configuration file: a command section followed by option=value lines. Blank lines and comments starting with '#' are ignored.

```ini
[command]
option=value
...
```

--------------------------------

### Example command line: prog -v --report report.txt foo bar

Source: https://docs.python.org/3.2/library/optparse.html

Illustrates the terminology with a concrete command line: -v and --report are options, report.txt is an option argument (assuming --report takes one), and foo and bar are positional arguments.

```bash
prog -v --report report.txt foo bar
```

--------------------------------

### ContextDecorator example with decorator and with statement

Source: https://docs.python.org/3.2/library/contextlib.html

Shows a custom context manager inheriting from ContextDecorator. It prints 'Starting' and 'Finishing' around the block. The example includes usage as a decorator and with a with statement, showing the output.

```python
from contextlib import ContextDecorator

class mycontext(ContextDecorator):
    def __enter__(self):
        print('Starting')
        return self

    def __exit__(self, *exc):
        print('Finishing')
        return False
```

```python
>>> @mycontext()
... def function():
...     print('The bit in the middle')
...
>>> function()
Starting
The bit in the middle
Finishing
```

```python
>>> with mycontext():
...     print('The bit in the middle')
...
Starting
The bit in the middle
Finishing
```

--------------------------------

### Switch between multiple languages

Source: https://docs.python.org/3.2/library/gettext.html

Create multiple translation instances for different languages and switch between them by calling install() on the desired instance. The example creates instances for English, French, and German and installs them sequentially.

```python
import gettext

lang1 = gettext.translation('myapplication', languages=['en'])
lang2 = gettext.translation('myapplication', languages=['fr'])
lang3 = gettext.translation('myapplication', languages=['de'])

# start by using language1
lang1.install()

# ... time goes by, user selects language 2
lang2.install()

# ... more time goes by, user selects language 3
lang3.install()
```

--------------------------------

### setup.py for building noddy and noddy2 modules

Source: https://docs.python.org/3.2/extending/newtypes.html

Python setup script using distutils to build the noddy and noddy2 extension modules from C sources.

```python
from distutils.core import setup, Extension
setup(name="noddy", version="1.0",
      ext_modules=[
         Extension("noddy", ["noddy.c"]),
         Extension("noddy2", ["noddy2.c"]),
         ])
```

--------------------------------

### Create and write configuration file with configparser

Source: https://docs.python.org/3.2/library/configparser.html

Shows how to create a ConfigParser object, populate it using dictionary-like access, and write it to 'example.ini'. The DEFAULT section provides default values for all other sections.

```python
>>> import configparser
>>> config = configparser.ConfigParser()
>>> config['DEFAULT'] = {'ServerAliveInterval': '45',
...                      'Compression': 'yes',
...                      'CompressionLevel': '9'}
>>> config['bitbucket.org'] = {}
>>> config['bitbucket.org']['User'] = 'hg'
>>> config['topsecret.server.com'] = {}
>>> topsecret = config['topsecret.server.com']
>>> topsecret['Port'] = '50022'     # mutates the parser
>>> topsecret['ForwardX11'] = 'no'  # same here
>>> config['DEFAULT']['ForwardX11'] = 'yes'
>>> with open('example.ini', 'w') as configfile:
...   config.write(configfile)
...
```

--------------------------------

### Timing a user-defined function with import setup

Source: https://docs.python.org/3.2/library/timeit.html

Pass a setup parameter containing an import statement to give timeit access to functions defined in the script. The example defines a test function and times it.

```python
def test():
    """Stupid test function"""
    L = [i for i in range(100)]

if __name__ == '__main__':
    import timeit
    print(timeit.timeit("test()", setup="from __main__ import test"))
```

--------------------------------

### Set screen size and position with turtle.setup()

Source: https://docs.python.org/3.2/library/turtle.html

Shows two calls to screen.setup() with different argument types. The first sets the window to 200x200 pixels at the upper left of the screen. The second sets the window to 75% of screen width by 50% of screen height and centers it.

```python
>>> screen.setup (width=200, height=200, startx=0, starty=0)
>>>              # sets window to 200x200 pixels, in upper left of screen
>>> screen.setup(width=.75, height=0.5, startx=None, starty=None)
>>>              # sets window to 75% of screen by 50% of screen and centers
```

--------------------------------

### timeit.Timer with gc.enable() setup

Source: https://docs.python.org/3.2/library/timeit.html

Example showing how to re-enable garbage collection during timing by passing 'gc.enable()' as the setup string to the Timer constructor. This is useful when GC is an important component of the measured function's performance.

```python
timeit.Timer('for i in range(10): oct(i)', 'gc.enable()').timeit()
```

--------------------------------

### Pass SWIG options in setup.py

Source: https://docs.python.org/3.2/distutils/setupscript.html

Shows how to pass SWIG options to the Extension constructor using the swig_opts parameter. The example defines an extension '_foo' from 'foo.i' with options '-modern' and '-I../include'.

```python
setup(...,
      ext_modules=[Extension('_foo', ['foo.i'],
                             swig_opts=['-modern', '-I../include'])],
      py_modules=['foo'],
     )
```

--------------------------------

### curses chgat example

Source: https://docs.python.org/3.2/whatsnew/2.6.html

Shows using stdscr.chgat to bold text starting at y=0, x=21 for the rest of the line.

```python
# Boldface text starting at y=0,x=21
# and affecting the rest of the line.
stdscr.chgat(0, 21, curses.A_BOLD)
```
Tokens:
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