Making decisions

True or False

A comparison asks a question and gives back a boolean: True or False.

Comparison	Means
a < b, a > b	less than, greater than
a <= b, a >= b	less than or equal, greater than or equal
a == b	equal (two =, because one = stores a value)
a != b	not equal

Combine them with and (both must be true), or (at least one must be) and not:

angle >= 0 and angle <= 3.14

if, elif, else

if runs its indented block only when its condition is true. elif ("else if") tries another condition when the ones above were false, and else catches everything left over:

def describe(speed):
    if speed > 1.0:
        return "fast"
    elif speed > 0:
        return "moving"
    else:
        return "stopped"

Python checks the conditions from the top and runs only the first block whose condition is true. That's why the elif doesn't need to say speed <= 1.0: it's only reached when speed > 1.0 was false.

return ends the function straight away, so nothing after it runs.

Your task

1. Write choose_action(distance). The gripper is distance metres from a ball. Return "grab" when it's closer than 0.05 m, "approach" when it's closer than 0.5 m, and "wait" otherwise.
2. Write in_limits(angle, low, high). Return True when angle is between low and high, ends included, and False otherwise.

The grader tries values right on the boundaries, so think about < versus <=.