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Functions and Scope

A function is a block of code which only runs when it is called. You can pass data, known as parameters, into a function. A function can return data as a result.

Creating and Calling a Function​

In Python a function is defined using the def keyword. To call a function, use the function name followed by parenthesis.

def my_function():
  print("Hello from a function")

# Calling the function
my_function()

Arguments and Return Values​

Information can be passed into functions as arguments. Functions can also return a value using the return statement.

def multiply_by_two(x):
  return 5 * x

print(multiply_by_two(3)) # Outputs 15

Python Scope​

A variable is only available from inside the region it is created. This is called scope.

Local Scope​

A variable created inside a function belongs to the local scope of that function, and can only be used inside that function.

def myfunc():
  x = 300
  print(x)

myfunc()

Global Scope​

A variable created in the main body of the Python code is a global variable and belongs to the global scope. Global variables are available from within any scope, global and local.

x = 300

def myfunc():
  print(x)

myfunc()