Python

Introduction

Python is a general-purpose, high-level programming language whose design philosophy emphasizes code readability. Python's syntax allows programmers to express concepts in fewer lines of code than would be possible in languages such as C, and the language provides constructs intended to enable clear programs on both a small and large scale.

Python supports multiple programming paradigms, including object-oriented, imperative and functional programming styles. It features a fully dynamic type system and automatic memory management, similar to that of Scheme, Ruby, Perl and Tclm and has a large and comprehensive standard library.

Like other dynamic languages, Python is often used as a scripting language, but is also used in a wide range of non-scripting contexts. Using third-party tools, Python code can be packaged into standalone executable programs. Python interpreters are available for many operating systems.

CPython, the reference implementation of Python, is free and open source software and has a community-based development model, as do nearly all of its alternative implementations. CPython is managed by the non-profit Python Software Foundation.

Usage

OS and Processor Invocation Version(s)
Red Hat Linux (64-bit) % /util/bin/python
% /util/bin/python3
% /util/bin/python3.4
% /util/bin/python3.3
% /util/bin/python2.7
% /util/bin/python2.6
 3.4.3 (default)

Notes

  1. Exit python with: Ctrl-d or quit()
  2. If you want to use the latest /util/bin/python Python distribution, add /util/lib to your LD_LIBRARY_PATH environment variable. The system Python distribution available on RHEL systems in /usr/bin/python is installed by default and functions as part of the base operating system (OS). We can't modify it without destabilizing the OS. The default system Python doesn't include the Python libraries required by later versions of Python.

    Add /util/lib to your LD_LIBRARY_PATH environment variable with this command: 

    
% setenv LD_LIBRARY_PATH ${LD_LIBRARY_PATH}:/util/lib:

    ... then verify that the operation succeeded by printing the new value of your LD_LIBRARY_PATH environment variable: 

    
% printenv LD_LIBRARY_PATH
  3. Lisp users: Build Lisp including Python libraries by including: 

    /util/python/lib/python3.3

References

  1. http://en.wikipedia.org/wiki/Python_%28programming_language%29
  2. http://www.python.org/
  3. http://docs.python.org/tutorial/
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