英文:
Go regex, Negative Look Ahead alternative
问题
我正在尝试使用Go正则表达式实现(?<!\\{)\\[[a-zA-Z0-9_]+\\](?!\\})的匹配。
匹配的值将类似于[ua]和[ua_enc]，而不匹配的值应该是{[ua]}和{[ua_enc]}。
由于Go不支持负向前瞻，你可以使用什么替代表达式呢？
英文:
I am trying to implement the regex (?<!\\{)\\[[a-zA-Z0-9_]+\\](?!\\}) with go regex.
Match value will be like [ua] and [ua_enc] and unmatched should be {[ua]} and {[ua_enc]}
As Negative lookahead is not supported in Go, what may be the alternative expression for this?
答案1
得分: 2
对于这个问题，没有其他的替代表达方式。使用简单的 (?:[^{]|^)(...)(?:[^}]|$) 来捕获所需的匹配，并断言前后字符不是大括号，这种方法可能会有一些问题：你需要使用第一个捕获组而不是完整的匹配结果，并且当两个匹配之间只有一个字符时（例如 [foo]_[bar]），它会失败。最好的方法是使用 FindAllStringSubmatchIndex 并手动检查前后字符，以确保它们不是正则表达式外的大括号。
英文:
There is no alternative expression for this. Using plain (?:[^{]|^)(...)(?:[^}]|$) to capture the intended match and assert the previous and next characters are not braces will kind-of work: you will need to work with the first capture group instead of with the full match, and it will fail when there is only a single character between two matches (e.g. [foo]_[bar]). The best way, really, is to use FindAllStringSubmatchIndex and manually check the previous and next characters to make sure they are not braces outside of regexp.
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