Regular Expressions 101

Pro

^start of line

Non-Capturing Group(?:(?:1[89]|[2-9]\d) ?)?

?repeats the group contents below at most once:

Non-Capturing Group(?:1[89]|[2-9]\d)

1st Alternative1[89]

1the literal 1 (49₁₀ / 61₈ / 31₁₆)

Character Class[89]

8the literal 8 (56₁₀ / 70₈ / 38₁₆)

9the literal 9 (57₁₀ / 71₈ / 39₁₆)

2nd Alternative[2-9]\d

Character Class[2-9]

2-9one character from 2 (50₁₀) to 9 (57₁₀)

\da digit

?optionally matches the literal (32₁₀ / 40₈ / 20₁₆)

mthe literal m (109₁₀ / 155₈ / 6D₁₆) (case sensitive)

Non-Capturing Group(?: ?(?:1[89]|[2-9]\d))?

?repeats the group contents below at most once:

?optionally matches the literal (32₁₀ / 40₈ / 20₁₆)

Non-Capturing Group(?:1[89]|[2-9]\d)

1st Alternative1[89]

1the literal 1 (49₁₀ / 61₈ / 31₁₆)

Character Class[89]

8the literal 8 (56₁₀ / 70₈ / 38₁₆)

9the literal 9 (57₁₀ / 71₈ / 39₁₆)

2nd Alternative[2-9]\d

Character Class[2-9]

2-9one character from 2 (50₁₀) to 9 (57₁₀)

\da digit

$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.

25 tokens

^(?:(?:1[89]|[2-9]\d) ?)?m(?: ?(?:1[89]|[2-9]\d))?$

New

m18
18m
m 18
18 m

m18
18m
m 18
18 m