Pattern Matching In java for repeated pattern

Question

I want my string to match a pattern like this +cat,+dog,-name,+cat

So basically it should start with + or - followed by variable name and then ","

So I want to have a regex for the same for matching the string.

Could you please tell the regex for this pattern ?

What problems are you facing when writing such regex? What kind of help you need? — Pshemo, Dec 04 '17 at 16:50
I have this regex ^([+-][a-zA-Z0-9_]*,)*$ but I want that it should not end with ",". How shall I modify the expression ? — user3678399, Dec 04 '17 at 16:54
Possibly related: [Regex for Comma delimited list](https://stackoverflow.com/q/1396084) — Pshemo, Dec 04 '17 at 17:00

score 0 · Accepted Answer · answered Dec 04 '17 at 16:57

This regex matches one instance of "+/- plus a variable name":

[+-]\w+

Now, to make it so that it matches multiple instances of the above, separated by commas, change it like this:

[+-]\w+(,[+-]\w+)*

Basically, I added this part:

(,[+-]\w+)*

It is a group that can repeat zero or more times (*), in the group, there is a comma, followed by the first pattern we saw.

Basically, you just need to move the comma to the start of the capture group.

score 0 · Answer 2 · answered Dec 04 '17 at 17:02

0

Try this ==> ^[+-]\w*[,]

Hope this help!

answered Dec 04 '17 at 17:02

Nejib

2 Answers2