Python error explained

ZeroDivisionError: what it means and how to fix it

You divided by zero, which has no answer.

The message

ZeroDivisionError: division by zero

What it means

Dividing by zero is undefined in maths, so Python stops rather than give a made-up answer. It happens with /, // and %.

Common causes

• Working out an average of an empty list
• A count or total that turned out to be 0
• Percentages where the whole is 0

Example that raises it

def average(nums):
    return sum(nums) / len(nums)

print(average([4, 8, 6]))
print(average([]))

The fix

def average(nums):
    if not nums:
        return 0
    return sum(nums) / len(nums)

print(average([4, 8, 6]))
print(average([]))

Tip: Check for the empty case before dividing. An empty list is falsy, so "if not nums" catches it.

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