What Happens When

  1. Explain in simple terms the order of operations in the following program: when does the addition happen, when does the subtraction happen, when is each function called, etc.
  2. What is the final value of radiance?
radiance = 1.0
radiance = max(2.1, 2.0 + min(radiance, 1.1 * radiance - 0.5))
Show answer
    1. 1.1 * radiance = 1.1
    2. 1.1 - 0.5 = 0.6
    3. min(randiance, 0.6) = 0.6
    4. 2.0 + 0.6 = 2.6
    5. max(2.1, 2.6) = 2.6
  2. At the end, radiance = 2.6

Spot the Difference

  1. Predict what each of the print statements in the program below will print.
  2. Does max(len(rich), poor) run or produce an error message? If it runs, does its result make any sense?
easy_string = "abc"
print(max(easy_string))
rich = "gold"
poor = "tin"
print(max(rich, poor))
print(max(len(rich), len(poor)))
Show answer
  1. c
  2. tin

  3. 4

  4. It throws a TypeError. The command is trying to run max(4, 'tin') and you can’t compare a string and an integer

Why Not?

Why don’t max and min return None when they are given no arguments?

Show answer

max and min return TypeErrors in this case because the correct number of parameters was not supplied. If it just returned None, the error would be much harder to trace as it would likely be stored into a variable and used later in the program, which could lead to unintended behaviour.

See the notebook.

Back to Python basics - part one.