Defining Python Functions
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Create Function

def basic_function():

Use def to define a function with parenthesis for parameters. Optionally pass parameters (data) into the function to return a result.

Indent codelines in the body of the function. Any lines not indented will run before the function is called.

Run the function by calling it.

Example:

def greeting(): #define function.
  print("Hello!") #indented lines of code belong to function.
  print("This is my first function.")


greeting() #call the function.

Hello!
This is my first function.

Example:

def calcPercent(number, percent): #define parameters.
  numPercent = (number * percent) / 100
  print(numPercent,'%',sep='')


def main():
  number = float(input('Enter a number: '))
  percent = float(input('Enter a percent: '))
  calcPercent(number, percent) #pass user input into calcPercent.


main() #call the main function.

Enter a number: 220
Enter a percent: 10
22.0%

Example:

def calcPercent(number, percent): #define parameters.
  numPercent = (number * percent) / 100
  return numPercent


def main():
  number = float(input('Enter a number: '))
  percent = float(input('Enter a percent: '))
  print(calcPercent(number, percent),'%',sep='') #pass-in user input.


main() #call the function.

Enter a number: 220
Enter a percent: 10
22.0%

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