Regex to find sequence of words that can repeat

Question

I would like to identify the following pattern on a string (all words are separated by comma)
1. The string starts with RO,TA,PR
2. The string ends with TA,TO
3. After RO,TA,PR it can have multiples TA,PR

Example of valid patterns:
- RO,TA,PR,TA,TO
- RO,TA,PR,TA,PR,TA,TO
- RO,TA,PR,TA,PR,TA,PR,TA,TO
- RO,TA,PR,TA,PR,TA,PR,TA,PR,TA,TO
- RO,TA,PR,TA,PR,TA,PR,TA,PR,TA,TO

Example of invalid patterns:
- RO,PR,TA,TO
- RO,TA,TO,PR,TA,TO
- RO,TA,RO,TA,TO
- RO,TA,PR,TO

Look up the Keene closure `*` operator. Beyond that, you've already written the regex — Patrick Haugh, Dec 06 '16 at 16:25

score 0 · Accepted Answer · answered Dec 06 '16 at 16:28

0

you can try this: ^RO,TA,PR(,TA,PR)*,TA,TO$.

To begin with RO,TA,PR: ^RO,TA,PR

To end with ,TA,TO: ,TA,TO$

The star * repeat the regex inside () 0 or several times.

answered Dec 06 '16 at 16:28

Jean-Dominique

16
3

Regex to find sequence of words that can repeat

1 Answers1