Self-Information

Problem

Compute the self-information (surprisal) of an event with probability p:

I(p) = -ln(p)

Use the natural logarithm. Assume 0 < p <= 1.

Hint

Rare events carry more information; a certain event carries none.

case 1

in: [1]

expected: 0

case 2

in: [0.5]

expected: 0.6931471805599453

case 3

in: [0.25]

expected: 1.3862943611198906

case 4

in: [0.1]

expected: 2.3025850929940455

Starter codePython

import math
def self_information(p):
    # Your code here
    pass

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