如何用Python在文本文件中查找指定单词并输出其所在行

假设我们有一个名为example.txt的文本文件，内容如下：

steve 22 london

john 30 paris

alex 19 berlin

需求是查找指定单词（比如john），并输出该单词所在的整行内容，最终输出：

john 30 paris

以下是几种实现方案：

Python 实现 #

包含匹配（行中出现目标字符串即匹配） #

target_word = "john"
file_path = "example.txt"

with open(file_path, 'r') as file:
    for line in file:
        cleaned_line = line.strip()
        if cleaned_line and target_word in cleaned_line:
            print(cleaned_line)

精确单词匹配（仅匹配独立单词，避免误匹配johnny这类包含目标的字符串） #

target_word = "john"
file_path = "example.txt"

with open(file_path, 'r') as file:
    for line in file:
        cleaned_line = line.strip()
        if cleaned_line and target_word in cleaned_line.split():
            print(cleaned_line)

Shell 命令实现 #

包含匹配 #

grep "john" example.txt

精确单词匹配 #

grep -w "john" example.txt

内容的提问来源于stack exchange，提问作者Evan John