Python中的示例函数:计算单词

Question

我在Python中有点生疏,我只是在寻找帮助实现一个示例函数来计算单词(这只是一个scons脚本的示例目标,它没有做任何"真实"):

def countWords(target, source, env):
  if (len(target) == 1 and len(source) == 1):
    fin = open(str(source[0]), 'r')
    # do something with "f.read()"
    fin.close()

    fout = open(str(target[0]), 'w')
    # fout.write(something)
    fout.close()
  return None

你能帮我填写一下细节吗？计算单词的常用方法是读取每一行,分成单词,并为行中的每个单词增加字典中的计数器; 然后输出,通过减少计数对单词进行排序.

编辑:我使用的是Python 2.6(确切地说是Python 2.6.5)

Answer 1

from collections import defaultdict

def countWords(target, source, env):
    words = defaultdict(int)
    if (len(target) == 1 and len(source) == 1):
        with open(str(source[0]), 'r') as fin:
            for line in fin:
                for word in line.split():
                    words[word] += 1

        with open(str(target[0]), 'w') as fout:
            for word in sorted(words, key=words.__getitem__, reverse=True):
                fout.write('%s\n' % word)
    return None