the spot where a thousands comma goes
Matches the spot where a thousands comma goes. It finds the match anywhere inside the text. There is 1 capture group.
Pattern
/\B(?=(\d{3})+(?!\d))/- Match scope
- anywhere inside the text
- Capture groups
- 1
- What it catches in the first example
- ""
Try it yourself
Type any text and the parts this expression catches are highlighted. It runs in your browser and is never sent anywhere.
112341234567
11234567
1000
3 matches
Examples that match
- 1234567
- 1000
Examples that do not match
- 100
- 12
Other expressions in this group
\d+(?= dollars)a number followed by a certain word^(?!admin$).+$anything except this one word(?<=\$)\d+a number preceded by a certain sign(?<!\$)\b\d+a number without that sign in front^(?=.*[A-Z])(?=.*\d)(?=.*[a-z]).{8,}$eight or more characters with upper, lower and a digit^(?!.* ).+$text with no double space anywhere^(?=.*@).+$text that must contain this signHow 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 spot where a thousands comma goes?
\B(?=(\d{3})+(?!\d)).
Q. Which strings match?
Text like 1234567 matches; text like 100 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.