Repeating code

In this chapter we will learn about "loops", where programs can go back, iterate, and continue learning. It's one of the most important pieces of the programming puzzles!

Loops

In this section, we will look more closely at repeating code, loops, and the difference between the keywords for and while.
Looping turtles

In this section, we will see how we can simplify and enhance earlier programs using loops.
Text

In this section, we will look a little closer at manipulating text, and see what we can do with variables that contain strings.
Lists

In this section we will see how to collect more than one value in a variable using lists. In this way, we can collect a lot of information in one and the same place.
Follow instructions

In this section, we will continue with lists and see how to change them, and see an example of how useful empty lists can be.

There are many computers in a car, including one that shows the speed on the dashboard. But it's not just a once, it has to repeatedly check how fast the wheels are moving, figure out what that means for speed, and display it. And it should not stop until the car is turned off. The only way to do this is by using loops.

When you watch video on YouTube, it is not a still image, but several images one after the other, up to 60 different ones per second. These are received over the internet and drawn one at a time in a loop. Part of the loop is also waiting a few extra milliseconds (thousandths of a second, it's a long time in the computer world) for the images to come in at the right rate. Otherwise, the video would fast forward.

Difficulty level

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