统计一个文件中某个单词的出现次数

首先有一个最简单的方法，就是用正则匹配

import re
tmp = open("123.txt", "r").read()
print len(re.findall("hello", tmp))

还可以利用Counter来实现更多的功能

import collections
import re
 
pa = re.compile("\w+")
counter = collections.Counter(patt.findall(open('reparser.py','rt').read()))
 
# top 100
for word, times in counter.most_common(100):
    print word, times
 
# find word
counter_dict = dict(counter.most_common(0))
tobefind = 'hello'
print tobefind, counter_dict.get(tobefind, 0)