python - 如果文本文件内容中存在几个字符，则获取整个单词

Question

我有一个包含 100 多个段落的文本文件。我想查找并列出包含特定字符串的单词。

这是我的文本文件内容:

A computer is a general purpose device that can be programmed to carry out a set of arithmetic or logical operations automatically. Since a sequence of operations can be readily changed, the computer can solve more than one kind of problem.

我想检索包含ra的单词。它应该返回 常规、编程和操作。

这是我的代码:

with open('computer.txt', 'r') as searchfile:
    for line in searchfile:
        if "ra" in line:
            line_split = line.split(' ')
            for each in line_split:
                if "ra" in each:
                    print each

最有效的方法是什么？

Answer 1

正则表达式在这里可以很好地工作:

>>> import re
>>> r = re.compile(r"\b\w*ra\w*\b")
>>> r.findall("A computer is a general purpose device that can be programmed to carry out a set of arithmetic or logical operations automatically. Since a sequence of operations can be readily changed, the computer can solve more than one kind of problem.")
['general', 'programmed', 'operations', 'operations']

此列表包含重复项，可以通过简单的 set() 调用删除这些重复项(这又会删除元素的顺序，因此如果您需要保留它，则需要做更多的工作)。

请注意，正则表达式对于“单词”的理解相当幼稚:

\b   # Start of an alphanumeric word
\w*  # Match any number of word characters [A-Za-z0-9_]
ra   # Match ra
\w*  # Match any number of word characters
\b   # End of a word