RegEx: Grabbing values between quotation marks

I've been using the following with great success:

(["'])(?:(?=(\\?))\2.)*?\1

It supports nested quotes as well.

For those who want a deeper explanation of how this works, here's an explanation from user ephemient:

([""']) match a quote; ((?=(\\?))\2.) if backslash exists, gobble it, and whether or not that happens, match a character; *? match many times (non-greedily, as to not eat the closing quote); \1 match the same quote that was use for opening.

In general, the following regular expression fragment is what you are looking for:

"(.*?)"

This uses the non-greedy *? operator to capture everything up to but not including the next double quote. Then, you use a language-specific mechanism to extract the matched text.

In Python, you could do:

>>> import re
>>> string = '"Foo Bar" "Another Value"'
>>> print re.findall(r'"(.*?)"', string)
['Foo Bar', 'Another Value']

I would go for:

"([^"]*)"

The [^"] is regex for any character except '"'
The reason I use this over the non greedy many operator is that I have to keep looking that up just to make sure I get it correct.

Peculiarly, none of these answers produce a regex where the returned match is the text inside the quotes, which is what is asked for. MA-Madden tries but only gets the inside match as a captured group rather than the whole match. One way to actually do it would be :

(?<=(["']\b))(?:(?=(\\?))\2.)*?(?=\1)

Examples for this can be seen in this demo https://regex101.com/r/Hbj8aP/1

The key here is the the positive lookbehind at the start (the ?<= ) and the positive lookahead at the end (the ?=). The lookbehind is looking behind the current character to check for a quote, if found then start from there and then the lookahead is checking the character ahead for a quote and if found stop on that character. The lookbehind group (the ["']) is wrapped in brackets to create a group for whichever quote was found at the start, this is then used at the end lookahead (?=\1) to make sure it only stops when it finds the corresponding quote.

The only other complication is that because the lookahead doesn't actually consume the end quote, it will be found again by the starting lookbehind which causes text between ending and starting quotes on the same line to be matched. Putting a word boundary on the opening quote (["']\b) helps with this, though ideally I'd like to move past the lookahead but I don't think that is possible. The bit allowing escaped characters in the middle I've taken directly from Adam's answer.

I liked Eugen Mihailescu's solution to match the content between quotes whilst allowing to escape quotes. However, I discovered some problems with escaping and came up with the following regex to fix them:

(['"])(?:(?!\1|\\).|\\.)*\1

It does the trick and is still pretty simple and easy to maintain.

Demo (with some more test-cases; feel free to use it and expand on it).

_{PS: If you just want the content between quotes in the full match ($0), and are not afraid of the performance penalty use:}

(?<=(['"])\b)(?:(?!\1|\\).|\\.)*(?=\1)

_{Unfortunately, without the quotes as anchors, I had to add a boundary \b which does not play well with spaces and non-word boundary characters after the starting quote.}

_{Alternatively, modify the initial version by simply adding a group and extract the string form $2:}

(['"])((?:(?!\1|\\).|\\.)*)\1

_{PPS: If your focus is solely on efficiency, go with Casimir et Hippolyte's solution; it's a good one.}

This version

• accounts for escaped quotes

• controls backtracking

  /(["'])((?:(?!\1)[^\\]|(?:\\\\)*\\[^\\])*)\1/
  

Unlike Adam's answer, I have a simple but worked one:

(["'])(?:\\\1|.)*?\1

And just add parenthesis if you want to get content in quotes like this:

(["'])((?:\\\1|.)*?)\1

Then $1 matches quote char and $2 matches content string.

All the answer above are good.... except they DOES NOT support all the unicode characters! at ECMA Script (Javascript)

If you are a Node users, you might want the the modified version of accepted answer that support all unicode characters :

/(?<=((?<=[\s,.:;"']|^)["']))(?:(?=(\\?))\2.)*?(?=\1)/gmu

Try here.

echo 'junk "Foo Bar" not empty one "" this "but this" and this neither' | sed 's/[^\"]*\"\([^\"]*\)\"[^\"]*/>\1</g'

This will result in: >Foo Bar<><>but this<

Here I showed the result string between ><'s for clarity, also using the non-greedy version with this sed command we first throw out the junk before and after that ""'s and then replace this with the part between the ""'s and surround this by ><'s.

A supplementary answer for the subset of Microsoft VBA coders only one uses the library Microsoft VBScript Regular Expressions 5.5 and this gives the following code

Sub TestRegularExpression()

    Dim oRE As VBScript_RegExp_55.RegExp    '* Tools->References: Microsoft VBScript Regular Expressions 5.5
    Set oRE = New VBScript_RegExp_55.RegExp

    oRE.Pattern = """([^""]*)"""


    oRE.Global = True

    Dim sTest As String
    sTest = """Foo Bar"" ""Another Value"" something else"

    Debug.Assert oRE.test(sTest)

    Dim oMatchCol As VBScript_RegExp_55.MatchCollection
    Set oMatchCol = oRE.Execute(sTest)
    Debug.Assert oMatchCol.Count = 2

    Dim oMatch As Match
    For Each oMatch In oMatchCol
        Debug.Print oMatch.SubMatches(0)

    Next oMatch

End Sub

My solution to this is below

(["']).*\1(?![^\s])

Demo link : https://regex101.com/r/jlhQhV/1

Explanation:

(["'])-> Matches to either ' or " and store it in the backreference \1 once the match found

.* -> Greedy approach to continue matching everything zero or more times until it encounters ' or " at end of the string. After encountering such state, regex engine backtrack to previous matching character and here regex is over and will move to next regex.

\1 -> Matches to the character or string that have been matched earlier with the first capture group.

(?![^\s]) -> Negative lookahead to ensure there should not any non space character after the previous match