Tier 8 · Novicematch
The Dot Matters
Match strings containing "a.b" — with a real full stop between them.
An unescaped dot means "any character". To mean an actual dot, escape it: \. — this is the single most common regex bug in production code.
Your pattern0 chars · par 4
//
Flags
Start typing — tests run as you go.0 of 5 visible tests passing
Test cases
a.bmust matchthe a.b thingmust matchaxbmust not matcha naive dot would match this
aabmust not matchabmust not match
+ 7 hidden tests, checked when you submit. They are what stops a pattern that only fits the examples above.