* ** the role and

• In front of python difference function parameters single asterisk (*) and double asterisk (**) in

  • * The arbitrary number of arguments passed to the function tuple

    >>> def foo(param1, *param2):
            print param1
            print param2
    >>> foo(1,2,3,4,5)
    1
    (2, 3, 4, 5)

  • In addition, another usage single asterisk are extracting the parameter list:

    >>> def foo(bar, lee):
            print bar, lee
    >>> l = [1, 2]
    >>> foo(*l)
    1 2

  • Double asterisk ( ): kwargs
    parameters in the dictionary introduced in the form of

    >>> def bar(param1, **param2):
            print param1
            print param2
    >>> bar(1,a=2,b=3)
    1
    {'a': 2, 'b': 3}