<aside> 🌳 Real-life Example Imagine you have a box of chocolates, and you want to share one with each of your five best friends. Instead of saying, "Give a chocolate to Amy, then give a chocolate to Bob, then give a chocolate to Charlie,..." and so on, it would be so much easier to say, "Give a chocolate to each of my five best friends."

That's what a for loop does in coding! It lets you do something many times without writing it over and over.

</aside>

Video Explanation

https://youtu.be/1tniJYEEORA

What is a for loop?

A for loop is like a mini-instruction manual that tells the computer: "Do this task for each item in this group."

How can you use it?

Let's look at an example. Imagine you have many lines that look almost the same, like:

m[7][0] = (21, 0, 89)
m[7][1] = (21, 0, 89)
m[7][2] = (21, 0, 89)
m[7][3] = (21, 0, 89)
m[7][4] = (21, 0, 89)
m[7][5] = (21, 0, 89)
m[7][6] = (21, 0, 89)
m[7][7] = (21, 0, 89)

This can be shortened using a loop:

for column in range(0, 8):
	m[7][column] = (21, 0, 89)

Here's what's happening:

• range(0, 8) gives us a group of numbers: 0, 1, 2, ..., 6, 7.
• The for loop says: "For each number in this group, set column to the next number and do the task inside the loop."
• The task inside the loop is just m[7][column] = (21, 0, 89) where column is replaced by the number.

So, the computer sets each pixel m[7][0], m[7][0], …, m[7][0] to your desired color.

Using this idea, you can tackle programming pixels in multiple rows at once:

for column in range(0, 8):
	m[7][column] = (21, 0, 89)
	m[6][column] = (32, 0, 133)

And so on...

You’ll find many patterns like above, where you can use a loop to replace repeated lines.