Python: Essential Reference, Third Edition

The apply() Function

The apply(funcname, [, args [, kwargs]]) function is used to invoke a function indirectly where the arguments have been constructed in the form of a tuple or dictionary. args is a tuple containing the positional argument to be supplied to the function. If omitted, no arguments are passed. kwargs is a dictionary containing keyword arguments. The following statements produce identical results:

foo(3,"x", name='Dave', id=12345)

or

apply(foo, (3,"x"), { 'name': 'Dave', 'id': 12345 })

In older versions of Python, apply() was the only mechanism for calling a function in which the arguments were contained in a tuple or dictionary. This capability is now handled by the following syntax:

 a = (3,"x") b = { 'name' : 'Dave', 'id': 12345 ...