Javascript Regex to match value of JSON key value pair

Question

Given the following key value pairs, how could I match just the values (including the quotes)?

Explanation: I'm doing a find and replace in my IDE. I have hundreds of key/value pairs where the values need to be changed from strings to objects. So basically replacing the value.

"ElevationFilenameIn": "Input raster elevation file",
"TargetCRS": "Target vertical coordinate reference system Type",
"featureName": "The name of the feature to extract, for example \"Vegetation\" or \"Water\"",
"TargetCRScode": "Target vertical coordinate system Code",
"TargetCRSfile": "The projection (.prj) file in shoebox to be used for this inputfile"

My attempt (which is not working, not even close):

[:]\s*(\"\w*\")

You can use [`JSON.parse(string)[key_name]`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/JSON/parse) — Washington Guedes, May 03 '16 at 14:36
You can use ("(.*?)") but I doubt if that is what you really need/want — , May 03 '16 at 14:43
No need to bracket the colon, or even include it in the regex. This should do it... `(\".*\"),` Do not forget to add that trailing comma in your replacement. — MichaelK, May 03 '16 at 14:44
@user6188402 Yes, that could be a possibility as well. I've updated my question to include escaped quotes. — bflemi3, May 03 '16 at 14:47
With or without escaped quotes, you can parse the string to get the object and then access the key's value — Washington Guedes, May 03 '16 at 14:48
@MichaelKarnerfors That will match the keys, not just the values. That's why he has the colon. — Barmar, May 03 '16 at 14:48
@user6188402 How do you parse a string in an IDE's find/replace dialogue? — Barmar, May 03 '16 at 14:49
@MichaelKarnerfors So now it will match from the beginning of the key to the end of the value. — Barmar, May 03 '16 at 14:53
See http://stackoverflow.com/questions/249791/regex-for-quoted-string-with-escaping-quotes for how to match a quoted string including escaped quotes inside it. — Barmar, May 03 '16 at 14:53
@Barmar: so add a lazy directive then. I cannot do that at the moment as I am now on a mobile device and in a hurry. :) — MichaelK, May 03 '16 at 15:02
@MichaelKarnerfors Laziness won't solve the problem. That will cause the regexp to stop as soon as a match is found, but doesn't make it start later than necessary. That's why he needs to skip over the `:` before starting. — Barmar, May 03 '16 at 15:08
@Barmar A match will not be found on the key because there is a **comma** at the end of the regex. So the regex will match the value and the comma, with the first replacement group being the value (quotes included). — MichaelK, May 03 '16 at 15:12
@MichaelKarnerfors There's no comma after the last value, so it won't match that one. — Barmar, May 03 '16 at 15:13
@MichaelKarnerfors When you get to a real browser, I suggest you try your idea at regex101.com. — Barmar, May 03 '16 at 15:14
@Barmar That last value he can replace manually. And **you** can be a smidgeon helpful, see the spirit of what I am trying to do and post a viable solution in stead of laying effort on going "that won't work" over and over. :-/ — MichaelK, May 03 '16 at 15:32
@MichaelKarnerfors Someone already posted an answer, and I posted a link to a related question. Why didn't you post your solution as an answer if you think it's right? — Barmar, May 03 '16 at 15:42

score 12 · Accepted Answer · answered May 03 '16 at 14:52

12

You can use the pattern:

[:]\s(\".*\")

and test it following this link: https://regex101.com/r/nE5eV3/1

answered May 03 '16 at 14:52

demartis

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what if it was a object e.g. `"ElevationFilenameIn": { "foo": "bar" }` – Edwin O. Aug 06 '19 at 14:30
@EdwinIkechukwu, do you need to match the entire string `{ "foo": "bar" }` including braces? – demartis Aug 06 '19 at 17:47
How to get a single value based on the key? – Niroshan K Mar 05 '22 at 09:13
This fails if multiple key value pairs present in same line eg. https://regex101.com/r/AgpwcS/1 – Karthik Rao May 19 '22 at 06:41

score 7 · Answer 2 · answered May 03 '16 at 15:30

7

I guess this one does the job also well. One good part it doesn't use any capture groups one bad part it's more costly compared to the accepted answer.

[^:]+(?=,|$)

Regular expression visualization

Debuggex Demo

Regex101 Demo

answered May 03 '16 at 15:30

Redu

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and `[^:\"]+(?=,|$)` to get rid of the quotes :) – Alejandro Mar 12 '19 at 19:35

Jesse de gans · Answer 3 · 2020-11-02T17:02:09.637

2

Get value

[^:"]+(?="})

Get value by key

If you wish to select a specific key that can be done like so:

[^:KEY"]+(?="})

edited Nov 02 '20 at 17:02

answered Aug 10 '20 at 00:11

Jesse de gans

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Is this working? – Niroshan K Mar 06 '22 at 12:58

score 2 · Answer 4 · answered Mar 18 '21 at 13:04

2

All key value par in complex JSON object.

"[a-zA-Z0-9 -]*"(?=:):[a-zA-Z0-9 "-ć]*(?<=")|"[a-zA-Z0-9 -]*"(?=:):[a-zA-Z0-9 "-ć]*(?=,)|"[a-zA-Z0-9 -]*"(?=:):[a-zA-Z0-9 "-ć]*(?=\w+)

answered Mar 18 '21 at 13:04

Pavle Nožinić

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score 1 · Answer 5 · answered Apr 17 '22 at 18:13

1

To get a value by itself without capturing the key:

(?:\"keyname)(?:\"\s?:\s?\")(.*)(?:\")

For example given:

{"keyname":"value"}

This will capture

value

Test here: https://regex101.com/r/Bm1mmK/1

answered Apr 17 '22 at 18:13

Akumaburn

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score 0 · Answer 6 · answered Dec 15 '21 at 15:19

Here's one that works when the value is another json object:

:\s*["{](.*)["}]\s*[,}]

It does not include the quotes/brackets in the capture group. If you want to include those, the capture group is easily modified:

:\s*(["{].*["}])\s*[,}]

The expressions also handle varying whitespace since json ignores whitespace.

Javascript Regex to match value of JSON key value pair

6 Answers6

Get value

Get value by key

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