📝 Dynamic Behavior in Python

Python includes a lot of flexibility and can adjust DataTypes and behaviors based on valid operations on inputs provided.

*args

Sometimes when you build functions you do not know how many inputs you will have. This can be handled usings *args.

Note

Any *variable can be used for *args, it is convention and good practice to use *args

def add(*args):
    print(sum(args), type(args))


add(2, 3)

5 <class 'tuple'>

**kwargs

Sometimes you want to input an arbitrary number of key-value pairs. This can be done with the **kwargs input.

Note

Any **variable can be used for **kwargs, it is convention and good practice to use *kwargs

def add(**kwargs):
    print(kwargs)  # this is a dictionary
    print(sum(kwargs.values()))


add(two=2, three=3)

{'two': 2, 'three': 3}
5

*args and **kwargs

You can use predefined inputs, *args, and **kwargs together. Python will choose the right input.

def add(text, *args, **kwargs):
    print(text + f"kwargs is: {sum(kwargs.values())}")
    print(text + f"args is: {sum(args)}")


add("the sum is:", two=2, three=3)

the sum is:kwargs is: 5
the sum is:args is: 0

add("the sum is:", 2, 3)

the sum is:kwargs is: 0
the sum is:args is: 5

add("the sum is:", 2, 100, three=3, _1k=1000)

the sum is:kwargs is: 1003
the sum is:args is: 102

Note

*args and **kwargs are much more useful with iterators which you will learn about soon.

Dynamic Typing

Within functions it is possible to input different DataTypes as inputs and as long a python can infer a valid operation and DataType it will automatically adjust

def multiplier(x, y):
    print(f"multiplier ({x}, {y}) is {x * y}")
    print(type(x * y))

multiplier(3, 2)

multiplier (3, 2) is 6
<class 'int'>

multiplier(3.14, 2)

multiplier (3.14, 2) is 6.28
<class 'float'>

multiplier("Drexel Dragons ", 3)

multiplier (Drexel Dragons , 3) is Drexel Dragons Drexel Dragons Drexel Dragons 
<class 'str'>