Regular Expressions 101

Negative Lookbehind(?<![\p{Letter}\d_])

Character Class[\p{Letter}\d_]

\p{Letter}any Unicode letter

\da digit

_the literal _ (95₁₀ / 137₈ / 5F₁₆)

testthe literal text test (case insensitive)

Negative Lookahead(?![\p{Letter}\d_])

Character Class[\p{Letter}\d_]

\p{Letter}any Unicode letter

\da digit

_the literal _ (95₁₀ / 137₈ / 5F₁₆)

Global pattern flags

g modifier: global. Finds all matches instead of stopping after the first

m modifier: multiline. Causes ^ and $ to match the start and end of each line, not only the start and end of the string

u modifier: unicode. Enables Unicode-aware matching and escape syntax

i modifier: insensitive. Matches without distinguishing uppercase and lowercase letters

Detailed match information will be displayed here automatically.

Search reference

Regular Expression

(?<![\p{Letter}\d_])test(?![\p{Letter}\d_])

teststring
testö
testœ
test1
test_

test.
test,
test/
test

stringtest
ötest
œtest
1test
_test

.test
,test
/test
test