Python文本处理2个小案例（文本嗅探与关键词占比统计）

问题描述：有一些句子和一些关键词，现在想找出包含至少一个关键词的那些句子（文本嗅探），可以参考print('='*30)之前的代码。如果想进一步计算每个句子中的关键词占比（句子中所有关键词长度之和/句子长度），可以参考后面的代码。关键词占比是比较常用的一个文本分类标准，如果想根据关键词占比对句子进行分类的话，可以自行补充代码。

本文主要演示列表推导式、字符串对象用法以及生成器表达式和内置函数的用法。

from random import choice

from string import ascii_letters

def check(sentences, words):

    '''返回包含至少一个关键词的句子列表'''

    return [sentence \

            for sentence in sentences\

            if sum(sentence.count(word)\

                   for word in words)>0]

sentences = ['This is a test.',

             'Beautiful is better than ugly.',

             'Explicit is better than implicit.',

             'Simple is better than complex.',

             'Sparse is better than dense.',

             'Readability counts.',

             'Now is better than never.']

words = ['test', 'count', 'dense', 'is', 'simple']

result = check(sentences, words)

for item in result:

    print(item)

print('='*30)

# 计算每个句子中所有关键字总长度的占比

d = {sentence:round(sum(sentence.count(word)*len(word)\

                        for word in words)/len(sentence),3)\

     for sentence in result}

for item in d.items():

    print(item)

运行结果：

This is a test.

Beautiful is better than ugly.

Explicit is better than implicit.

Simple is better than complex.

Sparse is better than dense.

Readability counts.

Now is better than never.

==============================

('This is a test.', 0.533)

('Beautiful is better than ugly.', 0.067)

('Explicit is better than implicit.', 0.061)

('Simple is better than complex.', 0.067)

('Sparse is better than dense.', 0.25)

('Readability counts.', 0.263)

('Now is better than never.', 0.08)