Session 4, #1: Drawing Shapes with Loops
A loop allows you to repeat commands multiple times. For example, this program will draw a square:
Let's examine what each line does in the program:
| 1 | import turtle | Directs Python to load the turtle package, so, we can use the commands in it. |
|---|---|---|
| 2 | Blank lines are ignored by Python. | |
| 3 | ty = turtle.Turtle() | Creates a variable called ty. Variables store information while our program is running. ty keeps track of the location and direction facing. |
| 4 | ty.color("orange") | Change ty's color to be orange. |
| 5 | Blank lines are ignored by Python. | |
| 6 | for i in range(4): | The for loop repeats the indented statements below it. |
| 7 | ty.forward(100) | Move ty forward 100 steps. |
| 8 | ty.left(90) | Turn ty 90 degrees to the left. |
By changing the range(), we change the number of times the loop repeats.