Regular Expressions 101

^start of line

Group 1(\w+)

\w+any word character, repeated at least once

=the literal text =

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

\na line-feed (newline) character (ASCII 10)

Positive Lookahead(?=((?!\b\1\b)[^!])*(^\1 =|\Z))

Group 2((?!\b\1\b)[^!])*

*repeats the group contents below any number of times:

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

\ban ASCII word boundary

\1the text saved by group 1

\ban ASCII word boundary

Negated Character Class[^!]

!the literal ! (33₁₀ / 41₈ / 21₁₆)

Group 3(^\1 =|\Z)

1st Alternative^\1 =

^start of line

\1the text saved by group 1

=the literal text =

2nd Alternative\Z

\Zend of string, or before its final line terminator

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

^(\w+) =.*\n(?=((?!\b\1\b)[^!])*(^\1 =|\Z))

Test String
New

a = 10
a * 3

foo = 8
2 - 1
b = 18

c = 10
d = 8
d = 4
cd = 72  
d / 6
d + 1

e = 1
e = 2
e + 1

FooBar1 = 0
Fuz__ = 8
Fuz__ / 1

f = 1
f + 1
f = 2
f + 1

g = 1
1 / 5 * 8 + 4

Regular Expression

Test StringNew

SubstitutionProcessing...

Test String
New

Substitution
Processing...