If you want to reuse code, you can use a function.

This prevents you from writing the same thing over and over again.

A function has a unique distinct name in the program. Once you call a function it will execute one or more lines of codes, which we will call a code block.

Related Course: Python Crash Course: Master Python Programming

Function example

For example, we could have the Pythagoras function.

In case your math is a little rusty, a^2 + b^2 = c^2. Thus, c = sqrt( a^2 + b^2). In code we could write that as:

import math

def pythagoras(a,b):
value = math.sqrt(a *a + b*b)


We call the function with parameters a=3 and b =3 on the last line. A function can be called several times with varying parameters. There is no limit to the number of function calls.

Note: The def keyword tells Python we define a function. Always use four spaces to indent the code block, using another number of spaces will throw a syntax error.

Return value

It is also possible to store the output of a function in a variable. To do so, we use the keyword return.

import math

def pythagoras(a,b):
value = math.sqrt(a*a + b*b)
return value

result = pythagoras(3,3)

The function pythagoras is called with a=3 and b=3. The program execution continues in the function pythagoras.

The output of math.sqrt(aa + bb) is stored in the function variable value. This is returned and the output is stored in the variable result. Finally, we print variable result to the screen.

Previous Post Next Post

Cookie policy | Privacy policy | ©