Regular Expressions 101

Explanation

Pro

^start of line

Group 1(\S+(?:.*\b(?=[XVI])X?(?:IX|IV|V?I{0,3})\b(?= +\S))?)

\S+any non-whitespace character, repeated at least once

Non-Capturing Group(?:.*\b(?=[XVI])X?(?:IX|IV|V?I{0,3})\b(?= +\S))?

?repeats the group contents below at most once:

.*any character (except for line terminators), repeated any number of times

\ba Unicode word boundary

Positive Lookahead(?=[XVI])

Character Class[XVI]

Xthe literal X (88₁₀ / 130₈ / 58₁₆) (case sensitive)

Vthe literal V (86₁₀ / 126₈ / 56₁₆) (case sensitive)

Ithe literal I (73₁₀ / 111₈ / 49₁₆) (case sensitive)

X?optionally matches the literal X (88₁₀ / 130₈ / 58₁₆) (case sensitive)

Non-Capturing Group(?:IX|IV|V?I{0,3})

1st AlternativeIX

IXthe literal text IX (case sensitive)

2nd AlternativeIV

IVthe literal text IV (case sensitive)

3rd AlternativeV?I{0,3}

V?optionally matches the literal V (86₁₀ / 126₈ / 56₁₆) (case sensitive)

I{0,3}the literal I (73₁₀ / 111₈ / 49₁₆) (case sensitive), repeated between 0 and 3 times

\ba Unicode word boundary

Positive Lookahead(?= +\S)

+the literal (32₁₀ / 40₈ / 20₁₆) , repeated at least once

\Sany non-whitespace character

+the literal (32₁₀ / 40₈ / 20₁₆) , repeated at least once

Group 2(.*)

.*any character (except for line terminators), repeated any number of times

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

Match Information

Detailed match information will be displayed here automatically.

Quick Reference

27 tokens

Regular Expression

^(\S+(?:.*\b(?=[XVI])X?(?:IX|IV|V?I{0,3})\b(?= +\S))?) +(.*)

New

Vladimir Goth
Langraab II Landgraab
Léa Magdalena X Rouault Something
Anna Maria Teodora
Léa Maria Teodora II

Langraab XIV Landgraab
Léa Magdalena XIX Rouault Something
Anna Maria Teodora
Léa Maria Teodora XX
Léa Maria Teodora XX NO 20 SUPPORT!!!