Drawing with Loops

Finally, we are back to turtles! Let's start with a program that draws a octagon (8 sides)...

import turtle turtle.forward(40) turtle.left(45) turtle.forward(40) turtle.left(45) turtle.forward(40) turtle.left(45) turtle.forward(40) turtle.left(45) turtle.forward(40) turtle.left(45) turtle.forward(40) turtle.left(45) turtle.forward(40) turtle.left(45) turtle.forward(40) turtle.left(45)

That's a lot of forward and left! An octagon has 8 sides, so we need to repeat that 8 times. Can we use a for loop to shorten the program? Here's an example using a for loop...

import turtle for a in range(8): turtle.forward(40) turtle.left(45)

The range will generate a list with 8 items, so the for loop will repeat 8 times. Each time, we will make the turtle go forward and turn left by 45 degrees. We are not using the variable a, so you can just ignore it.

Ex 1. Other shapes (part 2)

In an earlier challenge, we drew different shapes using the turtle module. Let's do that again, but this time, use a for loop to simplify it. Can you draw...

Triangle
Square
Pentagon (5 sides)
Hexagon (6 sides)

Ex 2. Any shapes

Can you write a program that asks the user for a number, then draw a shape with that number of sides? Here's a hint: The turn command should use an angle that is equal to 360 / number_of_sides. The first line has been written for you.

number_of_sides = input("How many sides?")