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Here's what new-style classes have to offer: Properties: Attributes that are defined by get/set methods Static methods and class methods The new __getattribute__ hook, which, unlike __getattr__, is called for every attribute access, not just when the attribute can't be found in the instance Descriptors: A protocol to define the behavior of attribute access through objects Overriding the constructor __new__ Metaclasses (not discussed)

This script mimics rsync which is available for the unix platform and have been ported to win32 one. It is a sort of advanced version of xcopy. Its aim is to selectively synchronize folders. More precisely it copy selective parts of a folder to a destination folder and in addition can remove parts of the destination folder that do not correspond to parts of the original folder. I like its capability to avoid copying files through the .cvsignore mechanism or the pattern matching mechanism and its capability to delete files that are no longer relevant, not to mention that because it's a python script anyone can easily fix or improve it as he whish.

What idioms should I use to make my code easier to read? Read "The Python Cookbook", especially the first few chapters. It's a great source of well-written Python code examples.

Use function factories to create utility functions. Often, especially if you're using map and filter a lot, you need utility functions that convert other functions or methods to taking a single parameter. In particular, you often want to bind some data to the function once, and then apply it repeatedly to different objects. In the above example, we needed a function that multiplied a particular field of an object by 3, but what we really want is a factory that's able to return for any field name and amount a multiplier function in that family:

Use zip and dict to map fields to names. zip turns a pair of sequences into a list of tuples containing the first, second, etc. values from each sequence. For example, zip('abc', [1,2,3]) == [('a',1),('b',2),('c',3)]. You can use this to save a lot of typing when you have fields in a known order that you want to map to names:

pylize is a Python script that makes the creation of on-screen presentations a matter of a few minutes. It generates a template master document, which you can edit with your favourite text or HTML editor. The master document is then processed by pylize to generate HTML files for every slide plus a file for the table of contents. You can view the presentation with any CSS-capable webbrowser.

I hope this article encourages you to think about your command line programs in a different light, and to treat them as first class objects. Using inheritance to share code is so common in other areas of development that it is hardly given a second thought in most cases. As has been shown with the SQLiteAppBase programs, the same technique can be just as powerful when applied to building command line programs, saving development time and testing effort as a result. CommandLineApp has been used as the foundation for dozens of types of programs, and could be just what you need the next time you have to write a new command line program.

On Sat, 15 Dec 2001 17:53:49 -0800 (PST), David Brady <daves_spam_dodging_account at yahoo.com> wrote : >More win32all questions... is it possible to get the >handle of the window that currently has the focus? >win32gui.GetActiveWindow() fails because I'm looking >for a window outside the process of my Python script. E:\>python ActivePython 2.1.1, build 212 (ActiveState) Python 2.1.1 (#20, Jul 26 2001, 11:38:51) [MSC 32 bit (Intel)] on win32 Type "copyright", "credits" or "license" for more information. >>> import win32gui >>> import time >>> for x in range(10): ... time.sleep(1) ... print x, win32gui.GetWindowText(win32gui.GetForegroundWindow()) ... 0 cmd - python 1 cmd - python 2 (Untitled) * SciTE 3 (Untitled) * SciTE 4 ActivePython Documentation 5 ActivePython Documentation 6 PythonWin 7 PythonWin 8 PythonWin

You can "turn an ordinary function into a thread" using the Thread class: just pass the function as the value for the `target' argument: import threading threading.Thread(target=your_function).start()

he most popular cryptographic software for Windows is probably TrueCrypt. In this article I will explain how TrueCrypt works and as a by-product a working Python implementation will be provided. This article is written from a programmer perspective and the math will be kept to the minimum. The emphasis is on how TrueCrypt uses cryptographic primitives such as AES and SHA-1, not how the primitives themselves work.

in PyCrypto: >>> key = os.urandom(16) # Generate 16 random bytes (128 bits) >>> bin_to_hex(key) # Show the key in hex (32 characters) '61aa60e43a5e7fdb4b86a4897b52a0dc' >>> y = RFC1751.key_to_english(key) >>> y # Show the pass phrase version of the key 'BUSY BARN RUB DOLE TAUT TOOK ALTO PRY KIT WALL MUG CURT' >>> # The transformation is always reversible >>> bin_to_hex(RFC1751.english_to_key(y)) '61aa60e43a5e7fdb4b86a4897b52a0dc'

Human-Readable Encryption Keys

> Is there a way to find the number of processors on a machine (on linux/ > windows/macos/cygwin) using python code (using the same code/cross > platform code)? From processing <http://cheeseshop.python.org/pypi/processing/0.34> : def cpuCount():     '''     Returns the number of CPUs in the system     '''     if sys.platform == 'win32':         try:             num = int(os.environ['NUMBER_OF_PROCESSORS'])         except (ValueError, KeyError):             pass     elif sys.platform == 'darwin':         try:             num = int(os.popen('sysctl -n hw.ncpu').read())         except ValueError:             pass     else:         try:             num = os.sysconf('SC_NPROCESSORS_ONLN')         except (ValueError, OSError, AttributeError):             pass     if num >= 1:         return num     else:         raise NotImplementedError --

What's the relation between these benefits and Stackless's implementation details? Here's a quick sketch: Continuations are the general-purpose concurrency construct. A continuation represents all the future computations of a particular program. Capturing all this control flow in a single conceptual object makes it programmable: It becomes possible to calculate or reason over the control flow. In particular, there's great scope for optimizing assignment of different calculations to different processes or threads or even hosts.

What is Py++? Definition: Py++ is an object-oriented framework for creating a code generator for Boost.Python library. Py++ uses few different programming paradigms to help you to expose C++ declarations to Python. This code generator will not stand on your way. It will guide you through the whole process. It will raise warnings in the case you are doing something wrong with a link to the explanation. And the most important it will save your time - you will not have to update code generator script every time source code is changed.

PyInstaller is a program that converts (packages) Python programs into stand-alone executables, under Windows, Linux and Irix. Its main advantages over similar tools are that PyInstaller works with any version of Python since 1.5, it builds smaller executables thanks to transparent compression, it is multi-platform (so you can build one-file binaries also under Linux), and use the OS support to load the dynamic libraries, thus ensuring full compatibility. PyInstaller is an effort to rescue, maintain and further develop Gordon McMillan's Python Installer (now PyInstaller). Their official website is not longer available and the original package is not longer maintained. Believing that it is still far superior to py2exe, we have setup this site to continue its further development. Feel free to join us in the effort! Please consult our Roadmap to check our plans. Also usage reports are welcomed: let us know if PyInstaller works for you and how, or what problems you found in using it.

Description geopy makes it easy for developers to locate the coordinates of addresses, cities, countries, and landmarks across the globe using third-party geocoders and other sources of data, such as wikis. Development Status Under development since September 2006. Latest release: 0.93. License geopy is open source software released under the MIT license. Contact Questions, comments, and bug reports are welcome at exogen@gmail.com, the geopy mailing list, and on brian's blog.

Various Web surfing tasks that I regularly perform could be made much easier, and less tedious, if I could only use Python to fetch the HTML pages and to process them, yielding the information I really need. In this document I attempt to describe HTML processing in Python using readily available tools and libraries.