Ith occurrence of a character using Regular Expression

Question

How can i reach the i th character in a string using regular expressions?

For eg:

I have a string like this:

Jack,Jill,Mary,John,Joey

I want to reach the 2nd occurrence of comma and pick up the string between the 2nd and 3rd occurrence of comma, i.e. my regular expression should give me "Mary".

Is there any way this can be done using regular expressions?

score 5 · Answer 1 · answered Dec 23 '13 at 05:42

5

You can use this regex to capture text between 2nd and 3rd comma:

^(?:[^,]*,){2}([^,]*)

Online Demo: http://regex101.com/r/qU7fP7

answered Dec 23 '13 at 05:42

anubhava

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Instead of using regex, I feel this is easy to split based on `,` in the language which the OP use. – Praveen Dec 23 '13 at 05:45
Ya sure langage can also be used but not always possible. As you can see regex is not too complicated here. – anubhava Dec 23 '13 at 05:46
1

Ya you can do using split by coma, but user want in regex, so i agree with @anubhava solution. – James Sapam Dec 23 '13 at 05:51
+1 I'm able to understand the first part, however may I know what it represents `([^,]*)` even I tried here http://tinyurl.com/qyo2j2a to learn it. – Praveen Dec 23 '13 at 05:52
1

Yes question wants `mary` to be captured that's what the answer provides as you can see the demo link I provided. – anubhava Dec 23 '13 at 05:56
@PraveenJeganathan: `[^,]*` means match 0 or more characters until a comma is found. And `([^,]*)` means capture that string in a group. – anubhava Dec 23 '13 at 05:57
(\w+,){2}(\w+).* this also will do the same thing right ? it match in second group. – James Sapam Dec 23 '13 at 06:03
@yopy: In this example: `(?:\w+,){2}(\w+)` might work but `\w` means only `[A-Za-z0-9_]` so if input has for example spaces OR hyphen also then `\w` based regex will fail. – anubhava Dec 23 '13 at 06:05
1

nice online demo : +1 – Infinite Recursion Dec 23 '13 at 06:06
similar question, http://stackoverflow.com/questions/5422949/how-to-find-the-3rd-occurrence-of-a-pattern-on-a-line – James Sapam Dec 23 '13 at 06:27
@yopy: Yes but that is vim focussed where regex syntax is different. – anubhava Dec 23 '13 at 06:34

Ith occurrence of a character using Regular Expression

1 Answers1

Online Demo: http://regex101.com/r/qU7fP7