text with no double space anywhere
Matches text with no double space anywhere. It is anchored at both ends, so the whole string has to match. There are no capture groups.
Pattern
/^(?!.* ).+$/- Match scope
- the whole string
- Capture groups
- 0
- What it catches in the first example
- one two
Try it yourself
Type any text and the parts this expression catches are highlighted. It runs in your browser and is never sent anywhere.
one two
1 match
Examples that match
- one two
- a
Examples that do not match
- one two
- a b
Other expressions in this group
^(?!admin$).+$anything except this one word(?<=\$)\d+a number preceded by a certain sign(?<!\$)\b\d+a number without that sign in front^(?=.*[A-Z])(?=.*\d)(?=.*[a-z]).{8,}$eight or more characters with upper, lower and a digit^(?=.*@).+$text that must contain this sign\B(?=(\d{3})+(?!\d))the spot where a thousands comma goes^(?!.*(.)\1).+$no character repeated back to back(?<=₩)\d+digits that follow a won 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
QWhat is the regex for text with no double space anywhere?
^(?!.* ).+$.
QWhich strings match?
Text like one two matches; text like one two does not.
QDoes the whole string have to match?
Yes. It is wrapped in ^ and $, so nothing but a full match passes.
QHow 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.