Tag: functions

Functions

A function is reusable code that can be called anywhere in your program. Functions improve readability of your code: it’s easier for someone to understand code using functions instead of long lists of instructions.

On top of that, functions can be reused or modified which also improve testability and extensibility.
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Function definition

We use this syntax to define as function:

def function(parameters):
    instructions
    return value

The def keyword tells Python we have a piece of reusable code (A function). A program can have many functions.

Practical Example

We can call the function using function(parameters).

#!/usr/bin/python

def f(x):
    return(x*x)
    
print(f(3))

Output:

The function has one parameter, x. The return value is the value the function returns. Not all functions have to return something.

Parameters

We can pass multiple variables:

#!/usr/bin/python

def f(x,y):
    print('You called f(x,y) with the value x = ' + str(x) + ' and y = ' + str(y))
    print('x * y = ' + str(x*y))

f(3,2)

Output:


You called f(x,y) with the value x = 3 and y = 2
x * y = 6

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