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python - 如何仅将引号添加到感兴趣的子字符串？

问题描述

我编写了一个解析器，它能够从字符串中获取信息。我不知道如何在感兴趣的子字符串周围添加引号。让我举例说明：

我收到了这条消息：

message = 'I have two variables: -mass: 12 --vel= 18 OR this is just another descriptor AND that new thing OR that newfangled thing'

我需要在特定子字符串（遵循布尔运算符）周围添加引号，如下所示：

message = 'I have two variables: -mass: 12 --vel= 18 OR "this is just another descriptor" AND "that new thing" OR "that newfangled thing"'

我已经这样做了：

attributes = ['OR', 'AND', 'NOT']
message = 'I have two variables: -mass: 12 --vel= 18 OR this is just another descriptor AND that new thing OR that new fangled thing'
for attribute in attributes:
        modified_attribute = ' '+attribute+' '
        message = modified_attribute.join('"{}"'.format(s.strip()) for s in message.split(attribute))
        if attributes.index(attribute)>0: message = message[1:-1]

print(message)

但是，它返回了这个，这不是我想要的：

"I have two variables: -mass: 12 --vel= 18" OR "this is just another descriptor" AND "that new thing" OR "that new fangled thing"

上面的第一句应该有引号，因为它前面没有布尔运算符。我该怎么办？

编辑：我正在寻找一种可扩展的解决方案，可用于引用字符串中任意数量的子字符串。

标签： pythonstring

解决方案

您可以使用带有前瞻的正则表达式，如下所示：

import re
message = re.sub(r'(\b(?:{0})\b) (.*?)(?=\s*\b(?:{0}|$)\b)'.format('|'.join(map(re.escape, attributes))), r'\1 "\2"', message)

message会变成：

I have two variables: -mass: 12 --vel= 18 OR "this is just another descriptor" AND "that new thing" OR "that new fangled thing"

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