Python：如何使用关键字列表在文本中搜索字符串

问题描述

所以我正在编写一个程序，它会遍历多个 .txt 文件并搜索任意数量的预先指定的关键字。我在寻找传递要搜索的关键字列表的方法时遇到了一些麻烦。

以下代码当前返回以下错误：

TypeError: 'in <string>' requires string as left operand,not list

我知道错误是由关键字列表引起的，但我不知道如何输入大量关键字而不运行此错误。

当前代码：

from os import listdir

keywords=['Example','Use','Of','Keywords']
 
with open("/home/user/folder/project/result.txt","w") as f:
    for filename in listdir("/home/user/folder/project/data"):
        with open('/home/user/folder/project/data/' + filename) as currentFile:
            text = currentFile.read()
            #Error Below
            if (keywords in text):
                f.write('Keyword found in ' + filename[:-4] + '\n')
            else:
                f.write('No keyword in ' + filename[:-4] + '\n')

错误在上述代码的第 10 行注释部分下指出。我不确定为什么我不能调用列表来搜索关键字。感谢任何帮助，谢谢！

解决方法

尝试遍历列表以查看每个元素是否在文本中

for i in range(0,len(keywords)):
    if keywords[i] in text:
        f.write('Keyword found in ' + filename[:-4] + '\n')
        break
    else:
        f.write('No keyword in ' + filename[:-4] + '\n')
        break

您也不能使用 in 查看列表是否在字符串中

,

我会使用 regular expressions，因为它们是专门为搜索子字符串文本而构建的。

您只需要 re.search 块。我添加了 findall 和 finditer 的示例来揭开它们的神秘面纱。

# lets pretend these 4 sentences in `text` are 4 different files
text = '''Lorem Ipsum is simply dummy text of the printing and typesetting industry. Lorem Ipsum has been the industry's standard dummy text ever since the 1500s,when an unknown printer took a galley of type and scrambled it to make a type specimen book. It has survived not only five centuries,but also the leap into electronic typesetting,remaining essentially unchanged. It was popularised in the 1960s with the release of Letraset sheets containing Lorem Ipsum passages,and more recently with desktop publishing software like Aldus PageMaker including versions of Lorem Ipsum'''.split(sep='. ')

# add more keywords
keywords=[r'publishing',r'industry']
regex = '|'.join(keywords)
import re
for t in text:
    lst = re.findall(regex,t,re.I) # re.I make case-insensitive
    for el in lst:
        print(el)

    iterator = re.finditer(regex,re.I)
    for el in iterator:
        print(el.span())

    if re.search(regex,re.I):
        print('Keyword found in `' + t + '`\n')
    else:
        print('No keyword in `' + t + '`\n')

输出：

industry
(65,73)
Keyword found in `Lorem Ipsum is simply dummy text of the printing and typesetting industry`

industry
(25,33)
Keyword found in `Lorem Ipsum has been the industry's standard dummy text ever since the 1500s,when an unknown printer took a galley of type and scrambled it to make a type specimen book`

No keyword in `It has survived not only five centuries,remaining essentially unchanged`

publishing
(132,142)
Keyword found in `It was popularised in the 1960s with the release of Letraset sheets containing Lorem Ipsum passages,and more recently with desktop publishing software like Aldus PageMaker including versions of Lorem Ipsum`

,

你可以替换

if (keywords in text):
   ...

与

if any(keyword in text for keyword in keywords):
   ...