grouping without catching
Matches grouping without catching. It is anchored at both ends, so the whole string has to match. There are no capture groups.
Pattern
/^(?:\d{3}-)+\d{4}$/- Match scope
- the whole string
- Capture groups
- 0
- What it catches in the first example
- 123-456-7890
Try it yourself
Type any text and the parts this expression catches are highlighted. It runs in your browser and is never sent anywhere.
123-456-7890
1 match
Examples that match
- 123-456-7890
- 123-4567
Examples that do not match
- 1234567
- 123-
Other expressions in this group
^<.+>$one chunk, taken as long as possible^(?:cat|dog)$either one of two words^(?:ab)+$a two-letter group, repeated^(\d{3})-(\d{4})$two parts caught separately^(?<year>\d{4})-(?<month>\d{2})$catching with a name attached(\w)\1the same character twice in a row\b(\w+)\s+\1\bthe same word typed twice^(?:https?://)?example\.com$an address with or without the schemeHow 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 grouping without catching?
^(?:\d{3}-)+\d{4}$.
Q. Which strings match?
Text like 123-456-7890 matches; text like 1234567 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 are no capture groups, so only the whole match (match[0]) comes back. Wrap the part you need in brackets to capture it.