Loops

A loop lets you repeat instructions multiple times without writing the instructions out multiple times.

From:

create a variable
call a function
create a variable
call a function
create a variable
call a function....

To:

Repeat this 15 times:
  create a variable
  call a function

for loop, or a count-controlled loop

• executes a set of instructions for a specified number of times
• used if you know the number of times you need to repeat the instructions

iteration – one pass through the instructions

while loop, or condition-controlled loop

• repeats a set of instructions while that condition is true.

While there are pink tiles available:
  placeTile('pink')
  placeTile('orange')
  placeTile('mint')

for each loops

We define a sequence of desired tile colors (a list), and tell the computer to repeat the instructions for each item in the sequence. Here’s an example list:

festiveList = ['pink', 'green', 'red', 'pink', 'green', 'red' ]

and the loop would look like:

For each color in festiveList:
  placeTile(color)