EasyNLPnlp-038

Inverse Document Frequency

Problem

Return the inverse document frequency math.log(n_docs / df), where df is the number of documents that contain the term.

Return 0.0 when df is 0.

Hint

A term appearing in every document has idf 0.

case 1

in: [2,4]

expected: 0.6931471805599453

case 2

in: [4,4]

expected: 0

case 3

in: [0,5]

expected: 0

case 4

in: [1,1]

expected: 0

case 5

in: [1,10]

expected: 2.302585092994046

Starter codePython

import math
def idf(df, n_docs):
    # Your code here
    pass

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