For Loops


Control flow statements

  • Change the way your code runs
  • Different control flow statements allow you to repeatedly run the same block of code over and over, or even not run it at all!
  • For loops are one type of control flow statement
  • If/else statements are another type (which we will discuss later)

For loops

  • Write something once, then execute it over and over!
  • You have to know before you run a for loop how many times it will run


  • Line 1: for {loopVariable} in {loopList}:
    • {loopVariable} is an element of the list
    • {loopList} is the list to cycle through
  • Line 2+: tab, then statement to loop over

The len() Function

  • This gives the length of a list
  • Use this when cycling through a list! For an example, see Example 4 in the Playground!