raise ValueError and assert: Enforcing Your Docstring

When should a function raise its own ValueError, and when should an assert refuse to let the program continue at all?

Finger exercises

Short drills on what this video just taught. Write the code, run the checks, and reveal the answer only if you are stuck.

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Exercise 1 of 5

Walk two lists in step

Define pairwise_division(Lnum, Ldenom). Both arguments are non-empty lists of numbers of equal length. Return a new list holding each element of Lnum divided by the element sitting at the matching position of Ldenom. With [4, 5, 6] and [1, 2, 3] the result is [4.0, 2.5, 2.0].

A loop or a one-line comprehension are equally fine. (Hint: len() reports a list's length, range() counts up to it, and L.append(v) adds v to the end of a list.)

# Divide each element of Lnum by the element at the same position of Ldenom.
def pairwise_division(Lnum, Ldenom):
    """ Lnum and Ldenom are non-empty lists of equal length
        returns a new list of the pairwise divisions """
    # your code here
    return ...

# Divide each element of Lnum by the element at the same position of Ldenom.
def pairwise_division(Lnum, Ldenom):
    """ Lnum and Ldenom are non-empty lists of equal length
        returns a new list of the pairwise divisions """
    # your code here
    return ...

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pairwise_division is a function you can call

returns a list with one entry per position

divides the elements that share a position

returns a new list, leaving both inputs unchanged

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