Worksheet

0.3 Doing it again

Python quick start · Robot club · about 12 min

What this lesson is about

for and while, indentation, and a square drawn with three lines instead of eight.

• A loop that counts
• A square
• A loop that keeps going

Questions 7 marks in all

1. [1 mark]What does this program print?

   for i in range(4):
       print("this is time number", i)

2. [1 mark]What does this program print?

   for i in range(3):
       print("side")
   print("done")

3. [1 mark]What does this program print?

   for i in range(3):
       print(i * 10)

4. [1 mark]What does this program make the robot do?

   for i in range(4):
       forward(50, distance=25)
       turn_right(35, angle=90)
   stop()

   1. ADrive a square, turning clockwise, and finish near where it started
   2. BDrive one straight line 100 cm long
   3. CDrive a triangle
   4. DDrive a square, turning anticlockwise

5. [1 mark]You want the robot to drive a triangle with equal sides. How many degrees should turn_right turn at each corner?

6. [1 mark]The robot starts at heading 0 and runs turn_right(35, angle=90) three times. Ignoring small errors, what does heading() say? Give a whole number of degrees.

7. [1 mark]Why does a while loop that drives need a small wait() inside it?

   1. ASo time passes and the robot moves between looks; without it the loop spins as fast as it can
   2. BTo make the robot drive more slowly
   3. CPython gives an error for any loop without a wait
   4. DSo that clock() can start counting

The task: four corners

Drive a square: 30 cm a side, turning right at each corner, using a for loop. The four green squares are the corners it has to pass through.

from bugbot import *
connect()

for i in range(4):
    # one side and one corner
    forward(50, distance=30)

stop()

Plan your program here, then type it in and press Run.

Do it on the robot
www.bugbotlab.com/learn/start-3-loops/
The simulator checks it and tells you when it passes. Nothing to install, no account.

Challenges

1. Make the square go anticlockwise with turn_left.
2. Flash the light: for loop, led("red"), wait(0.2), led("off"), wait(0.2).
3. Drive a triangle. What angle does each corner need?