compression_compression.py

import math class HuffmanCode: def __init__(self, code): self.dic = {} self.code = {} self.l = len(code) for i in code: if i in self.code: self.code[i] += 1 else: self.code[i] = 1 for i in self.code: print(i, self.code[i], self.l) def entropy(self, probs): psum = 0 for i in probs: psum += i * math.log(i, 2) return -psum def coding(self): rank = list(reversed(sorted([(self.code[i], i) for i in self.code], key=lambda x: x[0]))) first = rank.pop() second = rank.pop() self.dic[first[1]] = '0' self.dic[second[1]] = '1' while rank: node = rank.pop() for i in self.dic: self.dic[i] = '0' + self.dic[i] self.dic[node[1]] = '1' print(self.dic) def bitrate(self): s = 0 for i in self.dic: s += len(self.dic[i]) * self.code[i] print(s, self.l, s / self.l) if __name__ == '__main__': code1 = 'aaaaaaadddbdeddaaaaeeddce' h = HuffmanCode(code1) h.coding() h.bitrate() entro = [] for i in h.code: entro.append(h.code[i] / float(h.l)) print(h.entropy(entro))