jb_Modules_in_Python.pptx jb_Modules_in_Python.pptx

jb_Modules_in_Python.pptx jb_Modules_in_Python.pptx

• 1.
  Modules in Python BY PAURUSHSINHA
• 2.
  What are Modules? Modulesare files containing Python definitions and statements (ex. name.py) A module’s definitions can be imported into other modules by using “import name” The module’s name is available as a global variable value To access a module’s functions, type “name.function()”
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  More on Modules Modules can contain executable statements along with function definitions  Each module has its own private symbol table used as the global symbol table by all functions in the module  Modules can import other modules  Each module is imported once per interpreter session  reload(name)  Can import names from a module into the importing module’s symbol table  from mod import m1, m2 (or *)  m1()
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  The Module SearchPath The interpreter searches for a file named name.py ◦ Current directory given by variable sys.path ◦ List of directories specified by PYTHONPATH ◦ Default path (in UNIX - .:/usr/local/lib/python) Script being run should not have the same name as a standard module or an error will occur when the module is imported
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  “Compiled” Python Files If files mod.pyc and mod.py are in the same directory, there is a byte- compiled version of the module mod  The modification time of the version of mod.py used to create mod.pyc is stored in mod.pyc  Normally, the user does not need to do anything to create the .pyc file  A compiled .py file is written to the .pyc  No error for failed attempt, .pyc is recognized as invalid  Contents of the .pyc can be shared by different machines
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  Standard Modules  Pythoncomes with a library of standard modules described in the Python Library Reference  Some are built into interpreter  >>> import sys >>> sys.s1 ‘>>> ‘ >>> sys.s1 = ‘c> ‘ c> print ‘Hello’ Hello c>  sys.path determines the interpreters’s search path for modules, with the default path taken from PYTHONPATH  Can be modified with append() (ex. Sys.path.append(‘SOMEPATH’)
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  Importing * Froma Package * does not import all submodules from a package Ensures that the package has been imported, only importing the names of the submodules defined in the package import sound.effects.echo import sound.effects.surround from sound.effects import *
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  Sources http://docs.python.org/tutorial/modules.html