Entropy calculation

entropy.py

#!/usr/bin/env python3

import math

def H(data):
    entropy = 0
    if not data:
        return entropy
    for x in range(256):
        p_x = float(data.count(chr(x))/len(data))
        if p_x > 0:
            entropy += -p_x*math.log(p_x, 2)
    return entropy

strings = [
    "dLLGIsy9Cn0avbjJRyMP7yoL",
    "gFnFcmVm8YT04uMmjafu28Cr"
    ]
for s in strings:
    print("{:3.3f} x {} = {:.1f}".format(H(s), len(s), len(s)*H(s)))

# 4.189 x 24 = 100.5
# 4.137 x 24 = 99.3