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"""
see: https://www.youtube.com/watch?v=umTbivyJoiI
"""
import sys
from math import log2
from collections import Counter
from bitarray.util import huffman_code
def efficiency(freq, code):
total = sum(freq.values()) # total frequency
H = 0.0 # entropy
L = 0.0 # average length
for s in freq.keys():
p = freq[s] / total # probability
H -= p * log2(p)
L += p * len(code[s])
print('H =', H)
print('L =', L)
return H / L # efficiency
if len(sys.argv) > 1:
with open(sys.argv[1], 'rb') as fi:
plain = fi.read()
else:
plain = b'aaabbbcde'
freq = Counter(plain)
code = huffman_code(freq)
print("Efficiency =", efficiency(freq, code))
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