如果句子前面有特定单词，则匹配一个单词

Question

I would like to match a word if there a specific word before in a sentence, for instance:

test1 foo test2 bar

I would like to match bar if foo is in the sentence before (and/or after bar ).

I tried:

(?<=(foo ([\w ]+)(?= bar)))bar

But doesn't work, the regex is incorrect because of + in lookbehind...

Could you please help me, thanks

Answer 1

If you have to use one regex, you can just simply move the [\\w ]+ out of the lookbehind. Then use an alternation to look for the word bar (on its own, not as part of another word) followed by foo as well:

((?<=foo)[\w ]+\bbar\b|\bbar\b[\w ]+(?=foo))

Regex101 demo