huffman_alphabet.zip_The Bat_huffman python

'''Copyright (c) 2013, Ceyhun Cakar All rights reserved. Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: 1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. 2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution. 3. All advertising materials mentioning features or use of this software must display the following acknowledgement: This product includes software developed by the <organization>. 4. Neither the name of the <organization> nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission. THIS SOFTWARE IS PROVIDED BY <COPYRIGHT HOLDER> ''AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL <COPYRIGHT HOLDER> BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. ''' import sys hidden_chars = {' ': 'SPACE', '\n': 'LF', '\r': 'CR', '\t': 'TAB'} class Huffman: def __init__(self, probabilities): sorted_list = sorted([(v, k) for k, v in probabilities]) self.characters = [[val[1]] for val in sorted_list] self.probabilities = [val[0] for val in sorted_list] self.codes = [['']] * len(self.probabilities) self.isReady = False def displayAlphabet(self): if self.isReady: max_code_size = max([len(code) for code in self.codes[0]]) print " -------------------" + "-"*max_code_size print "| New Alphabet " + " "*max_code_size + "|" print " -------------------" + "-"*max_code_size print "| Letter | Code" + " "*max_code_size + "|" print " -------------------" + "-"*max_code_size for (ch, code) in zip(self.characters[0], self.codes[0]): temp_c, shift_size = ch, 4 if ch in hidden_chars: temp_c, shift_size = hidden_chars[ch], 4- len(hidden_chars[ch]) print "| %s " % temp_c + ' '*shift_size + " | %s " % code + (" "*(max_code_size - len(code))) + "|" print " -------------------" + "-"*max_code_size else: print "Huffman Alphabet is NOT READY" def combine(self): least_probable_first = self.characters[0], self.probabilities[0], self.codes[0] least_probable_second = self.characters[1], self.probabilities[1], self.codes[1] self.characters, self.probabilities, self.codes = \ self.characters[2:], self.probabilities[2:], self.codes[2:] least_probable_group = [least_probable_first[0]+least_probable_second[0], least_probable_first[1]+least_probable_second[1], ['0' + it for it in least_probable_first[2]] + ['1' + it for it in least_probable_second[2]]] self.characters = [least_probable_group[0]] + self.characters self.probabilities = [least_probable_group[1]] + self.probabilities self.codes = [least_probable_group[2]] + self.codes combined = sorted(zip(self.probabilities, self.characters, self.codes)) self.probabilities = [val[0] for val in combined] self.characters = [val[1] for val in combined] self.codes = [val[2] for val in combined] self.isReady = (len(combined) == 1) return self.isReady if __name__ == '__main__': inp = 'karaparass' num_of_occurrence = {} for ch in inp: if not ch in num_of_occurrence.keys(): num_of_occurrence[ch] = 1 else: num_of_occurrence[ch] += 1 probs = {k:(v*1.0)/sum(num_of_occurrence.values()) \ for k,v in num_of_occurrence.items()} huff = Huffman(probs.items()) #huff.display() while not huff.combine(): pass huff.displayAlphabet()