Regular expressions·once or more

once or more

Matches once or more. It is anchored at both ends, so the whole string has to match. There are no capture groups.

Pattern
/^ab+c$/
Match scope
the whole string
Capture groups
0
What it catches in the first example
abc

Try it yourself

Type any text and the parts this expression catches are highlighted. It runs in your browser and is never sent anywhere.

abc

1 match

Examples that match

  • abc
  • abbc

Examples that do not match

  • ac
  • abd

Other expressions in this group

^ab*c$none or many^colou?r$a letter that may or may not be there^\d{4}$exactly four digits^\d{2,4}$between two and four digits^\d{2,}$two digits or more<.+?>one tag, taken as short as possible^<.+>$one chunk, taken as long as possible^(?:cat|dog)$either one of two words

How 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 once or more?

^ab+c$.

Q. Which strings match?

Text like abc matches; text like ac 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.