Regular expressions·any single character

any single character

Matches any single character. It is anchored at both ends, so the whole string has to match. There are no capture groups.

Pattern
/^.$/
Match scope
the whole string
Capture groups
0
What it catches in the first example
a

Try it yourself

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

a

1 match

Examples that match

  • a
  • 7
  • 가

Examples that do not match

  • ab
  • ""

Other expressions in this group

\wa letter, digit or underscore\Wanything that is not a word character\sa whitespace character\Sanything but whitespace^[a-z]+$lowercase letters only^[A-Z]+$uppercase letters only^[A-Za-z0-9]+$letters and digits only^[^0-9]+$text with no digits at all

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 any single character?

^.$.

Q. Which strings match?

Text like a matches; text like ab 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.