Hi There, In this post we’ll learn more about python functions.

Passing flexible number of arguments to a function

• In Python We can also pass N no. of arguments to a function as per our requirement. For this we have to use *args as parameter to that function.

• Example:

    >>> def sum_all_nums(*args):
    ...     total = 0
    ...     for num in args:
    ...         total += num
    ...     return total
    ...
    >>> sum_all_nums(1, 2, 3, 4, 5)
    15
    >>> sum_all_nums(1, 2)
    3
    >>> sum_all_nums(2, 4, 5, 6, 7, 2, 3, 4, 5 , 5, 7)
    50
    >>>
  

• In the above example we can observe that we called sum_all_nums function three time with different number of arguments this is because we have used *args as a parameter.
• Here the word args can be of any name Ex: *nums, *words.

**kwargs in Python

• The double asterisk form of **kwargs is used to pass a keyworded, variable-length argument dictionary to a function. You should use **kwargs if you want to handle named arguments in a function.

• Like *args, **kwargs can take however many arguments you would like to supply to it. However, **kwargs differs from *args in that you will need to assign keywords.

• *args and **kwargs make the function flexible.

• Usage of **kwargs:

    >>> def print_kwargs(**kwargs):
    ...     return kwargs
    ...
    >>> print_kwargs(name="Shark", age=24, weight=58)
    {'age': 24, 'name': 'Shark', 'weight': 58}
    >>>
  

Parameters ordering

• While passing the parameters to a function they should follow the below order if the function has below all arguments.

1. parameters
2. *args
3. default parameters
4. **kwargs

Tuple Unpacking

• Using * as an argument:

    >>> def unpack(*args):
    ...     return args
    ...
    >>> nums = [1, 2, 3, 4, 5]
    >>>
    >>> unpack(nums)
    ([1, 2, 3, 4, 5],)
    >>>
    >>>
    >>> unpack(*nums) #Tuple unpacking using *nums
    (1, 2, 3, 4, 5)
    >>>
  

• To unpack the values from a sequnce we need to pass * infornt of the sequence variable.

Dictonary Unpacking

• Using ** as an argument:

    >>> def display_names(a, b, c):
    ...     return a + b + c
    ...
    >>> nums = {'a': 1, 'b': 2, 'c': 3}
    >>>
    >>> display_names(**nums)
    6
  

• To unpack the values from a dictonary we need to pass ** infornt of the dictonary variable.