*args & **kwargs in Python

What do they do?

If you are here it’s probably because you’ve found these bits of code as part of a snippet of python code and couldn’t quite figure them out or you want to learn how to use them. Fear not, we are here to help.

In short **args & **kwargs allow you to pass an undetermined amount ( * & ** ) of arguments and named arguments (args = arguments &  kwargs = key-worded arguments).

Before fully explaining them, we need to take a step back and review some basics. Let’s start with functions ( we’ll check classes later ), I suggest you code along.

# A simple function with one argument or positional argument...
def simpleFunction(arg):
    return( 'I am a function, this is my argument: ' + arg )
print(simpleFunction('Argy'))
>>>
I am a function, this is my argument: Argy

           ------------------ • ------------------

# Now let's try key-worded arguments and 3 ways to add them when calling a function:
def simpleFunctionNamedArgs(arg1='Argy', arg2=2):
    return( 'I am a function, these are my named arguments: arg1=' + arg1 + ', arg2=' + str(arg2))
            ------------------ 1 ------------------
print(simpleFunctionNamedArgs())
>>> Default Arguments:
I am a function, these are my named arguments: arg1=Argy, arg2=2
            ------------------ 2 ------------------

print(simpleFunctionNamedArgs('Argidio', 4))
>>> Sequential Arguments
I am a function, these are my named arguments: arg1=Argidio, arg2=4
              
            ------------------ 3  ------------------
print(simpleFunctionNamedArgs(arg2=6, arg1='Argos’))
>>> Named Arguments, note the order doesn’t matter as long as the keywords fit the function definition:
I am a function, these are my named arguments: arg1=Argos, arg2=6

Summarized :