Replace first occurrence of the "," in the string with regex

Question

I have a issue with regex pattern. It replace not only "," but also all characters that are before.

I would like to replace first occurrence of the "," to ".":

"1,,000.23" -> "1.,000.23"

This pattern I am using now :

^(.*?),

Result that I receive is :

"1,,000.23" -> ".,000.23"

Expected result :

"1,,000.23" -> "1.,000.23"

What's a "firt" occurence? (why can't people spell check their questions?) — Boris the Spider, Feb 10 '18 at 11:03
It's doing what you're telling it to do. The `.*?` match whatever before the first `,` and you kill it. (I'm not sure, what's your replacement?) — user202729, Feb 10 '18 at 11:04
@user202729 how can I write pattern to replace only singe character ? — Oleg Gordiichuk, Feb 10 '18 at 11:04
Why not use `indexOf(',')` and `subString` and `replace`? It will be easier to reason about and quicker. Regex, if you are unfamaliar with it, causes more problems than it solves. — Boris the Spider, Feb 10 '18 at 11:08
[any-way-to-replace-characters-on-swift-string](https://stackoverflow.com/questions/24200888/any-way-to-replace-characters-on-swift-string) as alternate way to the (currently 3) answers/comments on how to do it — Patrick Artner, Feb 10 '18 at 11:17
@PatrickArtner thx for help but I was searching for regex for that. — Oleg Gordiichuk, Feb 10 '18 at 11:18

score 3 · Accepted Answer · answered Feb 10 '18 at 11:10

3

Maybe you could use ^([^,]+), and replace with $1.

This will capture from the beginning of the string ^ not a comma in a group ([^,]+) and then match a comma ,

answered Feb 10 '18 at 11:10

The fourth bird

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Patrick Artner · Answer 2 · 2018-02-10T11:11:54.830

3

Use ^(.*?), and replace it with $1.. This means:

group as less as possible things from line start till first , into group 1
then match a `,` 
and replace it with the captured text of group 1 `$1` and a dot `.`

See: https://regexr.com/3kjdq

edited Feb 10 '18 at 11:11

answered Feb 10 '18 at 11:10

Patrick Artner

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Wouldn't you be better off using a lookbehind? – Boris the Spider Feb 10 '18 at 11:10
@BoristheSpider Ways and rome :) I see already 3 different ones here to achieve the outcome ;) if he specs what regex exactly hes using ... – Patrick Artner Feb 10 '18 at 11:13

score 2 · Answer 3 · answered Feb 10 '18 at 11:10

2

Copy the capture group to the result. Replace

^(.*?),

with

$1

answered Feb 10 '18 at 11:10

Barmar

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Wouldn't you be better off using a lookbehind? – Boris the Spider Feb 10 '18 at 11:11
1

Need to find out what language he's using, so we know which advanced features are available. – Barmar Feb 10 '18 at 11:11
Now that we know he's using Swift, why don't you post the lookbehind answer? – Barmar Feb 10 '18 at 11:15

Replace first occurrence of the "," in the string with regex

3 Answers3