Regular Expressions 101

Pro

Negative Lookbehind(?<!([.\d\/]))

Group 1([.\d\/])

Character Class[.\d\/]

.the literal . (46₁₀ / 56₈ / 2E₁₆)

\da digit

\/the literal / (47₁₀ / 57₈ / 2F₁₆)

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

Group 2(\d+(?:\.\d+)?)

\d+a digit, repeated at least once

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

?repeats the group contents below at most once:

\.the literal . (46₁₀ / 56₈ / 2E₁₆)

\d+a digit, repeated at least once

Non-Capturing Group(?:\/(?2))?

?repeats the group contents below at most once:

\/the literal / (47₁₀ / 57₈ / 2F₁₆)

(?2)calls group 2 as a subroutine

Negative Lookahead(?!(?1))

(?1)calls group 1 as a subroutine

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

(?<!([.\d\/]))-?(\d+(?:\.\d+)?)(?:\/(?2))?(?!(?1))

New

-21.9/32.7
37/21.4
It's hot! (45.2 degrees)
16
Here is 26.3/17.4a
.01/2
1.2.3
.100.

-21.9/32.7
37/21.4
It's hot! (45.2 degrees)
16
Here is 26.3/17.4a
.01/2
1.2.3
.100.