Regular Expressions 101

^start of line

=the literal = (61₁₀ / 75₈ / 3D₁₆)

\?the literal ? (63₁₀ / 77₈ / 3F₁₆)

Group ifNull(?<ifNull>(?:\$\\\$*:|[^:])*)

Non-Capturing Group(?:\$\\\$*:|[^:])*

*repeats the group contents below any number of times:

1st Alternative\$\\\$*:

\\the literal \ (92₁₀ / 134₈ / 5C₁₆)

Group 2(\\\\)*

*repeats the group contents below any number of times:

\\the literal \ (92₁₀ / 134₈ / 5C₁₆)

:the literal : (58₁₀ / 72₈ / 3A₁₆)

2nd Alternative[^:]

Negated Character Class[^:]

:the literal : (58₁₀ / 72₈ / 3A₁₆)

Negative Lookbehind(?<!\\)

\\the literal \ (92₁₀ / 134₈ / 5C₁₆)

:the literal : (58₁₀ / 72₈ / 3A₁₆)

Group ifNotNull(?<ifNotNull>(?:\$\\\$*:|[^:])*)

Non-Capturing Group(?:\$\\\$*:|[^:])*

*repeats the group contents below any number of times:

1st Alternative\$\\\$*:

\\the literal \ (92₁₀ / 134₈ / 5C₁₆)

Group 4(\\\\)*

*repeats the group contents below any number of times:

\\the literal \ (92₁₀ / 134₈ / 5C₁₆)

:the literal : (58₁₀ / 72₈ / 3A₁₆)

2nd Alternative[^:]

Negated Character Class[^:]

:the literal : (58₁₀ / 72₈ / 3A₁₆)

$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.

Search reference

Regular Expression

^=\?(?<ifNull>(?:\\(\\\\)*:|[^:])*)(?<!\\):(?<ifNotNull>(?:\\(\\\\)*:|[^:])*)$

New

=?This value would be returned if null or empty.:This would be returned if not.
=?This\:is\:a\:demo of what \:happens\:with:an escaped \: separator.
=?This is what happens with an invalid value.
and don't forget the =? on the front of the string:or you won't get any results.

Regular Expression

Extraction