Capture text in quotes immediately before keyword - regex

Question

I have an input stream that looks like this:
"ignore this" blah "ignore this" blah "capture this" keyword "ignore this" blah
I want to capture capture this, i.e. the text in quotes before keyword.
I tried the regex (?:\"(.*)\" )(?=keyword), but this captures everything up to the quotation mark before keyword. How would I capture the text in quotes directly before keyword?

Answer 1

The pattern (?:\"(.*)\" )(?=keyword) matches the first " and then matches the last occurrence where a double quote followed by a space is followed by keyword because the dot also matches a double quote.
Note that in the pattern the non capturing group (?: can be omitted and the " does not have to be escaped.
You could use a negated character class instead to match any character except a "
The value is in the first capturing group.
"([^"]+)"(?= keyword)
Explanation
" Match literally
( Capturing group
[^"]+ Match 1+ times any char except "
) Close group
"(?= keyword) Match " and assert what is directly to the right is a space and keyword
Regex demo
An example using Javascript
const regex = /"([^"]+)"(?= keyword)/g;
const str = `"ignore this" blah "ignore this" blah "capture this" keyword "ignore this" blah`;
while ((m = regex.exec(str)) !== null) {
if (m.index === regex.lastIndex) {
regex.lastIndex++;
}
console.log(m[1]);
}

Answer 2

Try using lookaround assertions
var input = `"ignore this" blah "ignore this" blah "capture this" keyword "ignore this" blah`;
var result = /(?<=\")[A-Za-z0-9\ ]*(?=\" keyword)/i.exec(input)
console.log(result);
Here (?<=\") looks for content that follows " and (?=\" keyword) looks for content that is followed by " keyword.
More about Lookahead and Lookbehind Zero-Length Assertions here:
https://www.regular-expressions.info/lookaround.html

Answer 3

Your string to be captured or returned as a result is in between double quotes followed by a specific keyword. simply find that pattern that matches " followed by anything that is not " then followed by " keyword.
var input = `"ignore this" blah "ignore this" blah "capture this" keyword "ignore this" blah`;
var result = /(?=\")?[^"]+(?=\"\s*keyword)/i.exec(input)
console.log(result);