a group repeated exactly three times
Matches a group repeated exactly three times. It is anchored at both ends, so the whole string has to match. There is 1 capture group.
Pattern
/^(ab){3}$/- Match scope
- the whole string
- Capture groups
- 1
- What it catches in the first example
- ababab
Try it yourself
Type any text and the parts this expression catches are highlighted. It runs in your browser and is never sent anywhere.
ababab
1 match
Examples that match
- ababab
Examples that do not match
- abab
- ab
Other expressions in this group
^(?:https?://)?example\.com$an address with or without the scheme^(?:\d{1,3}\.){3}\d{1,3}$an address made of four parts^\d{0,3}$at most three digits^\w{3,8}$between three and eight word characters^(?:\w+\.){2}\w+$three parts separated by dots^/[a-z]+/?$a path whose trailing slash is optional^(cat|dog)$exactly one of two words^[a-c]{2,4}$two to four characters from a setHow to read this
- With ^ and $ around it, the whole string must match; without them the match can sit anywhere. Always anchor an expression you use for validation.
- Round brackets ( ) capture what they wrap. When you only need grouping, write (?: ) so the numbering of later groups does not shift.
- Every expression here is checked against its examples. Even so, "looks like an email" and "is a real inbox" remain different questions.
- Nested open-ended repeats such as (a+)+ can blow up on certain inputs. Look for that shape before pasting someone else’s expression into your code.
Frequently asked questions
Q. What is the regex for a group repeated exactly three times?
^(ab){3}$.
Q. Which strings match?
Text like ababab matches; text like abab does not.
Q. Does the whole string have to match?
Yes. It is wrapped in ^ and $, so nothing but a full match passes.
Q. How do I use what it caught?
There is one capture group, so you can read them from match[1] onwards.