PYTHON

star operator python

In a function call the '*' unpacks data structure of tuple or list into positional or keyword arguments to be received by function definition.

In a function call the '**' unpacks data structure of dictionary into positional or keyword arguments to be received by function definition.

In a function definition the '*' packs positional arguments into a tuple.

In a function definition the '**' packs keyword arguments into a dictionary.

star operator python

In function construction         In function call
=======================================================================
          |  def f(*args):                 |  def f(a, b):
*args     |      for arg in args:          |      return a + b
          |          print(arg)            |  args = (1, 2)
          |  f(1, 2)                       |  f(*args)
----------|--------------------------------|---------------------------
          |  def f(a, b):                  |  def f(a, b):
**kwargs  |      return a + b              |      return a + b
          |  def g(**kwargs):              |  kwargs = dict(a=1, b=2)
          |      return f(**kwargs)        |  f(**kwargs)
          |  g(a=1, b=2)                   |
-----------------------------------------------------------------------