‘‘‘
Allows?scoring?of?text?using?n-gram?probabilities
17/07/12
‘‘‘
from?math?import?log10

class?ngram_score（object）:
????def?__init__（selfngramfilesep=‘?‘）:
????????‘‘‘?load?a?file?containing?ngrams?and?counts?calculate?log?probabilities?‘‘‘
????????self.ngrams?=?{}
????????for?line?in?file（ngramfile）:
????????????keycount?=?line.split（sep）?
????????????self.ngrams[key]?=?int（count）
????????self.L?=?len（key）
????????self.N?=?sum（self.ngrams.itervalues（））
????????#calculate?log?probabilities
????????for?key?in?self.ngrams.keys（）:
????????????self.ngrams[key]?=?log10（float（self.ngrams[key]）/self.N）
????????self.floor?=?log10（0.01/self.N）

????def?score（selftext）:
????????‘‘‘?compute?the?score?of?text?‘‘‘
????????score?=?0
????????ngrams?=?self.ngrams.__getitem__
????????for?i?in?xrange（len（text）-self.L+1）:
????????????if?text[i:i+self.L]?in?self.ngrams:?score?+=?ngrams（text[i:i+self.L]）
????????????else:?score?+=?self.floor??????????
????????return?score

?屬性????????????大小?????日期????時間???名稱
-----------?---------??----------?-----??----
?????文件???????????0??2020-01-13?02:40??閫傚簲搴﹁綆?
?????文件????????6148??2020-01-13?02:40??閫傚簲搴﹁綆?.DS_Store
?????文件?????????120??2020-01-13?02:40??__MACOSX\閫傚簲搴﹁綆?._.DS_Store
?????文件?????????972??2019-11-29?01:12??閫傚簲搴﹁綆?ngram_score.py
?????文件??????975928??2019-11-29?01:08??閫傚簲搴﹁綆?english_quadgrams.txt.zip
?????文件?????????591??2019-11-29?01:08??__MACOSX\閫傚簲搴﹁綆?._english_quadgrams.txt.zip