Skip to content

Functions and Loops

What is a Function?

  • A function is a way to organize code into reusable sections.
  • It is a group of related statements that perform a specific task.
  • You can pass data, known as parameters, into a function.
  • A function can return data as a result.

Defining a Function

1
2
3
4
5
def forward():
    right_reverse.duty_u16(0)
    left_reverse.duty_u16(0)
    right_forward.duty_u16(32768)
    left_forward.duty_u16(32768)

Passing Variables into a Function

1
2
3
4
5
def forward(speed):
    right_reverse.duty_u16(0)
    left_reverse.duty_u16(0)
    right_forward.duty_u16(speed)
    left_forward.duty_u16(speed)

Returning a Result From a Function

1
2
3
def distanceToObject():
    # Some code
    return distance_cm

Calling a Function

1
2
forward(SPEED)
distance_cm = distanceToObject()

Using a Loop

A loop is a way to repeat the same action.

We can use a loop to have our car move in a square

1
2
3
4
5
6
for i in range(4):
    forward(SPEED)
    sleep(3)
    right(HALF_SPEED)
    sleep(1.5)
stop()

Let's examine the pieces of the for statement:

  1. Starts with the reserved word for
  2. Uses a variable that iterates
  3. Next is the reserved word in
  4. Finally, there is the data that is iterated over. In this example, we have a set (or range) of numbers. Note: a range is defined (by default) as starting at zero, so range(4) means that we are counting 0, 1, 2, 3.

Challenge

Rewrite the main.py code to use functions for forward, reverse, left, right, and stop

Use a loop so you don't "cut and paste" code

After your robot successfully moves in a square, can you make it move in an octogon route?