an invisible control character
Matches an invisible control character. It finds the match anywhere inside the text. There are no capture groups.
Pattern
/[\x00-\x1F]/- Match scope
- anywhere inside the text
- Capture groups
- 0
- What it catches in the first example
- \0
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 b
a
3 matches
Examples that match
- a\0b
- a
Examples that do not match
- abc
Other expressions in this group
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 an invisible control character?
[\x00-\x1F].
Q. Which strings match?
Text like a\0b matches; text like abc 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 are no capture groups, so only the whole match (match[0]) comes back. Wrap the part you need in brackets to capture it.