Regular Expressions 101

Explanation

Pro

\d+a Unicode decimal digit, repeated at least once

Positive Lookahead(?=((?:\s*(?:mmol|mm)-?[1-4]?){1,3}))

Group 1((?:\s*(?:mmol|mm)-?[1-4]?){1,3})

Non-Capturing Group(?:\s*(?:mmol|mm)-?[1-4]?){1,3}

{1,3}repeats the group contents below between 1 and 3 times:

\s*a Unicode whitespace character, repeated any number of times

Non-Capturing Group(?:mmol|mm)

1st Alternativemmol

mmolthe literal text mmol (case sensitive)

2nd Alternativemm

mmthe literal text mm (case sensitive)

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

Character Class[1-4]?

?matches at most one character from the set below:

1-4one character from 1 (49₁₀) to 4 (52₁₀)

\1the text saved by group 1

\ba Unicode word boundary

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+(?=((?:\s*(?:mmol|mm)-?[1-4]?){1,3}))\1\b

3 mmol mm
3 mmol2mm and 3 mmolmm

3 mmol mmb

3 mmol mm
3 mmol2mm and 3 mmolmm

3 mmol mmb