Regular Expressions 101

Negative Lookahead(?!^(?:\b(Example|Overflow|Test)\b(?!.*\b\1\b) *)+$)

^start of line

Non-Capturing Group(?:\b(Example|Overflow|Test)\b(?!.*\b\1\b) *)+

+repeats the group contents below at least once:

\ba Unicode word boundary

Group 1(Example|Overflow|Test)

1st AlternativeExample

Examplethe literal text Example (case sensitive)

2nd AlternativeOverflow

Overflowthe literal text Overflow (case sensitive)

3rd AlternativeTest

Testthe literal text Test (case sensitive)

\ba Unicode word boundary

Negative Lookahead(?!.*\b\1\b)

.*any Unicode character (except for line terminators), repeated any number of times

\ba Unicode word boundary

\1the text saved by group 1

\ba Unicode word boundary

*the literal (32₁₀ / 40₈ / 20₁₆) , repeated any number of times

$end of line

Non-Capturing Group(?:\b(Example|Overflow|Test)\b(?!.*\b\2\b) *)+

+repeats the group contents below at least once:

\ba Unicode word boundary

Group 2(Example|Overflow|Test)

1st AlternativeExample

Examplethe literal text Example (case sensitive)

2nd AlternativeOverflow

Overflowthe literal text Overflow (case sensitive)

3rd AlternativeTest

Testthe literal text Test (case sensitive)

\ba Unicode word boundary

Negative Lookahead(?!.*\b\2\b)

.*any Unicode character (except for line terminators), repeated any number of times

\ba Unicode word boundary

\2the text saved by group 2

\ba Unicode word boundary

*the literal (32₁₀ / 40₈ / 20₁₆) , repeated any number of times

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

Detailed match information will be displayed here automatically.

Search reference

Regular Expression

(?!^(?:\b(Example|Overflow|Test)\b(?!.*\b\1\b) *)+$)(?:\b(Example|Overflow|Test)\b(?!.*\b\2\b) *)+

New

Example Overflow Test Overflow
Example Overflow Test
Just an Example Overflow
Example another Overflow