the same word typed twice
Matches the same word typed twice. It finds the match anywhere inside the text. There is 1 capture group.
Pattern
/\b(\w+)\s+\1\b/- Match scope
- anywhere inside the text
- Capture groups
- 1
- What it catches in the first example
- the the
Try it yourself
Type any text and the parts this expression catches are highlighted. It runs in your browser and is never sent anywhere.
the the cat
is is
2 matches
Examples that match
- the the cat
- is is
Examples that do not match
- the cat
- this is
Other expressions in this group
^(?:cat|dog)$either one of two words^(?:ab)+$a two-letter group, repeated^(\d{3})-(\d{4})$two parts caught separately^(?:\d{3}-)+\d{4}$grouping without catching^(?<year>\d{4})-(?<month>\d{2})$catching with a name attached(\w)\1the same character twice in a row^(?:https?://)?example\.com$an address with or without the scheme^(?:\d{1,3}\.){3}\d{1,3}$an address made of four partsHow 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 the same word typed twice?
\b(\w+)\s+\1\b.
Q. Which strings match?
Text like the the cat matches; text like the cat does not.
Q. Does the whole string have to match?
No. It finds the part anywhere inside the text. Add ^ and $ around it if you want a whole-string check.
Q. How do I use what it caught?
There is one capture group, so you can read them from match[1] onwards.