Specific codes with a specific purpose(s) all together so they are maintainable and organized

A waste of time to use and it doesn't help your codes at all

Locate your codes in a single place so that it's easier to maintain

It's like a factory that may take into input (parameters) and process the input and give you a product (return)

helloWorld

shout HELLO WORLD as loud as you can

helloWorld()

print("Hello World")

It doesn't return a*b

It's missing two required parameters

the syntax of the function is wrong

False because the function is not equal to "Hello!"

False because "Hello!" is not equal to a

True because the voice_echo function will return "Hello!"

True because voice_echo function has been assigned to True by the return keyword

Sometimes function doesn't take parameters, sometimes it doesn't return anything, it all depends on your use case

return is only used when there is at least one parameter

using a return without parameter(s) is possible

We should always use functions to group our codes with specific purpose(s)

Local -> Enclosing -> Built-in -> Global

Built-in -> Global -> Enclosing -> Local

Enclosing -> Local -> Global -> Built-in

Local -> Enclosing -> Global -> Built-in

20

30

10

UnboundLocalError will be raised

To simplify our codes

So we can write thousands of line ourselves without using others' codes

So we can reuse a certain library that one has written in different programs

To save our time

import math as m

from math import * as a

from math import radians as rd

from math import sin