How to only catch what's between quotation marks in the following regex?

Question

The following regex matches substrings inside quotation marks:

^("[^"]*")$

"Dialogue," she said. "More dialogue."

I don't want to catch the quotation marks (only what's inside the quotation marks). So I figured I should use a lookahead and a lookbehind:

^((?<=")[^"]*(?="))$

But now the regex isn't matching anything.

Why is this? And how to fix it?

https://regexr.com/5spdt

EDIT: Removing the outer capture group kind of worked, but now she said is being caputerd too. (?<=")[^"]*(?=")

You can remove the anchors and the capture group `(?<=")[^"]*(?=")` — The fourth bird, May 12 '21 at 13:33
@Thefourthbird That kind of worked ... but now the `she said` is being captured too. — alexchenco, May 12 '21 at 13:34
For the example string, I only see a match for `Dialogue,` see https://regex101.com/r/J0lPpH/1 — The fourth bird, May 12 '21 at 13:35
@Thefourthbird That happens when there's another quote behind: https://regex101.com/r/CVSJxM/1 — alexchenco, May 12 '21 at 13:38
Then you might use `(?<=")[^"]*(?="(?:[^"]*"[^"]*")*[^"]*$)` https://regex101.com/r/dzO0ti/1 — The fourth bird, May 12 '21 at 13:41
@AD7six I don't want to capture the "'s. I only want to capture what's inside the "'s. — alexchenco, May 12 '21 at 13:44
Would a non-matching around your quotation marks group be sufficient to your needs? https://regexr.com/5spfj — Alexander Nied, May 12 '21 at 13:47
Does this answer your question? [How to replace captured groups only?](https://stackoverflow.com/questions/3954927/how-to-replace-captured-groups-only) — AD7six, May 12 '21 at 14:00

The fourth bird · Accepted Answer · 2021-05-12T14:05:15.230

1

You get too much matches, as the assertions to not match the " so anything between 2 double quotes is a match.

You can assert a " to the left, the match all except " until you can assert a " to the right followed by optional pairs of "" till the end of the string.

Assuming no escaped double quotes between the double quotes

 (?<=")[^"]*(?="(?:[^"]*"[^"]*")*[^"]*$)

(?<=") Positive lookbehind, assert " directly to the left of the current position
[^"]* Match 0+ times any char except "
(?= Positive lookahead, assert to the right
- " Match closing "
- (?:[^"]*"[^"]*")* Match optional pairs of ""
- [^"]*$ Match option char other than " and assert end of string
) Close lookahead

Regex demo

edited May 12 '21 at 14:05

answered May 12 '21 at 13:45

The fourth bird

154,723
16
55
70

1

@alexchenco I think it will be even longer if you want to allow escaped `\"` between the double quotes. – The fourth bird May 12 '21 at 13:46
It will be something like this https://regex101.com/r/rXeJfz/1 – The fourth bird May 12 '21 at 13:56

AD7six · Answer 2 · 2021-05-12T13:58:44.380

KISS

The regex in the question is overly specific (exploded):

^        # Start of string
(        # Begin capturing group
"
[^"]*
"
)        # End capturing group
$        # End of string

This will only match strings of the form:

"some string"

It would not, for example, match strings of the form:

anything "some string"   (does not start with a quote
"some string" anything   (does not end with a quote)

So given the goal is to capture quoted strings, just don't include the quotes in the capturing group:

"([^"]*)"

And then reference the capturing group, not the whole matching string.

Applied to Javascript

Consider the following code:

input = '"one" something "two" something "three" etc.';
regex = /"([^"]*)"/;
match = input.match(regex);

Match contains: ["\"one\"", "one"] - the 0 entry is the full matching string, the 1 entry is the first capturing group. Adapt js code as relevant.

I think you're right. I'm doing `.replace`, so I guess I can write `"..."` in the replace argument if I want to keep the quotes. — alexchenco, May 12 '21 at 13:55
er ok, so it's an x/y problem. Please always ask what you want to do, not how you are currently trying to solve it (:. — AD7six, May 12 '21 at 13:59

How to only catch what's between quotation marks in the following regex?

2 Answers2

KISS

Applied to Javascript