Regular Expressions 101

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

Character Class[-+.\d]

-the literal - (45₁₀ / 55₈ / 2D₁₆)

+the literal + (43₁₀ / 53₈ / 2B₁₆)

.the literal . (46₁₀ / 56₈ / 2E₁₆)

\da digit

Character Class[1-9]

1-9one character from 1 (49₁₀) to 9 (57₁₀)

\d*a digit, repeated any number of times

Group 1(\.\d+)?

?repeats the group contents below at most once:

\.the literal . (46₁₀ / 56₈ / 2E₁₆)

\d+a digit, repeated at least once

cmthe literal text cm (case sensitive)

Negative Lookahead(?![a-zA-Z])

Character Class[a-zA-Z]

a-zone character from a (97₁₀) to z (122₁₀) (case sensitive)

A-Zone character from A (65₁₀) to Z (90₁₀) (case sensitive)

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

(?<![-+.\d])[1-9]\d*(\.\d+)?cm(?![a-zA-Z])

New

80cm
80.2cm
80.25cm
71-80cm
-80.2cm
80 cm
80cmmm
08cm