python - 统计文本文件中字母出现的频率

Question

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Answer 1

使用collections.Counter() :

from collections import Counter
with open(file) as f:
    c = Counter()
    for line in f:
        c += Counter(line)

如果文件不是很大，你可以把它作为一个字符串全部读入内存，并用一行代码将它转换成一个Counter对象:

c = Counter(f.read())

例子:

>>> c = Counter()
>>> c += Counter('aaabbbcccddd eee fff ggg')
>>> c
Counter({'a': 3, ' ': 3, 'c': 3, 'b': 3, 'e': 3, 'd': 3, 'g': 3, 'f': 3})
>>> c += Counter('aaabbbccc')
Counter({'a': 6, 'c': 6, 'b': 6, ' ': 3, 'e': 3, 'd': 3, 'g': 3, 'f': 3})

或使用 count()字符串的方法:

from string import ascii_lowercase     # ascii_lowercase =='abcdefghijklmnopqrstuvwxyz'
with open(file) as f:
    text = f.read().strip()
    dic = {}
    for x in ascii_lowercase:
        dic[x] = text.count(x)