Regular Expressions 101

Pro

Positive Lookbehind(?<=Hello|^)

1st AlternativeHello

Hellothe literal text Hello (case sensitive)

2nd Alternative^

^start of line

Non-Capturing Group(?:(?!Hello|Goodbye).)+

+repeats the group contents below at least once:

Negative Lookahead(?!Hello|Goodbye)

1st AlternativeHello

Hellothe literal text Hello (case sensitive)

2nd AlternativeGoodbye

Goodbyethe literal text Goodbye (case sensitive)

.any character (except for line terminators)

Positive Lookahead(?=Goodbye|$)

1st AlternativeGoodbye

Goodbyethe literal text Goodbye (case sensitive)

2nd Alternative$

$end of line

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.

25 tokens

(?<=Hello|^)(?:(?!Hello|Goodbye).)+(?=Goodbye|$)

New

Hello, I like you. Goodbye.
Hello there, do you enjoy golf?
I like you. Goodbye. See you later.
Some text without delimiters

Hello, I like you. Goodbye.
Hello there, do you enjoy golf?
I like you. Goodbye. See you later.
Some text without delimiters