• A module is a file containing Python definitions and statements.
• A module's name is available through the __name__ variable.
• A module can be used by a script using the import statement.
• A module can contain executable statements and function definitions.
• The statements are only executed when the module is first imported via import statement.

#moduleA.py
print __name__

def print_str(str):
    print str

#script.py
import moduleA

moduleA.print_str('hello')

##output
moduleA
hello

• Each module has its own symbol table.
• Using from module import a you can import specific names from a module.
• from module import * imports all names except the ones beginning with an underscore.

if __name__=='__main__':
    #execute some code

# python <module.py>

• dir(module) lists the names defined in a module
• dir() lists the names defined in the current module

• For grouping a collection of modules

#sample package hierarchy

packageA/
    __init__.py
    packageB/
        __init__.py
        moduleB.py

#usage

import packageA.packageB.moduleB
or
from packageA.packageB import moduleB

moduleB.func()

from a.b import c <= c can be a package/module/function/variable/class

import a.b.c<= c has to be a package or a module, not a function/variable/class