Duplicate Detection Ratio

Problem

Compute the fraction of duplicate items in a dataset split.

Return (n - number of unique items) / n rounded to 4 decimal places, or 0.0 for an empty list.

case 1

in: [[1,2,2,3]]

expected: 0.25

case 2

in: [[1,1,1]]

expected: 0.6667

case 3

in: [[]]

expected: 0

case 4

in: [[1,2,3,4]]

expected: 0

Starter codePython

def duplicate_ratio(items):
    # Your code here
    pass

4 test cases · run your code against them in the editor