Regular Expressions 101

Pro

^start of line

-?optionally matches the literal - (45₁₀ / 55₈ / 2D₁₆)

Group 1(((?!00)\d+(?:\.{1}\d*)*)|((?!00)\d*(?:\.{1}\d+)))?

?repeats the group contents below at most once:

1st Alternative((?!00)\d+(?:\.{1}\d*)*)

Group 2((?!00)\d+(?:\.{1}\d*)*)

Negative Lookahead(?!00)

00the literal text 00

\d+a digit, repeated at least once

Non-Capturing Group(?:\.{1}\d*)*

*repeats the group contents below any number of times:

\.{1}the literal . (46₁₀ / 56₈ / 2E₁₆) , repeated exactly 1 time

\d*a digit, repeated any number of times

2nd Alternative((?!00)\d*(?:\.{1}\d+))

Group 3((?!00)\d*(?:\.{1}\d+))

Negative Lookahead(?!00)

00the literal text 00

\d*a digit, repeated any number of times

Non-Capturing Group(?:\.{1}\d+)

\.{1}the literal . (46₁₀ / 56₈ / 2E₁₆) , repeated exactly 1 time

\d+a digit, repeated at least once

$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.

26 tokens

^-?(((?!00)\d+(?:\.{1}\d*)*)|((?!00)\d*(?:\.{1}\d+)))?$

New

.5
0.500
3
0
0.0
.
00
00.5
-.5
-0.500
-3
-0
-0.0
-.
-00
-00.5

.5
0.500
3
0
0.0
.
00
00.5
-.5
-0.500
-3
-0
-0.0
-.
-00
-00.5