regex101: PCRE (Legacy) Substitution Workspace

\ba Unicode word boundary

Group 1( (?<abrev>(?:[A-Z]\.)+) |(?<roman>M{0,4}(?:CM|CD|D?C{0,3})(?:XC|XL|L?X{0,3})(?:IX|IV|V?I{0,3})) |(?<prep>(?i)d?[aoe]s?(?-i)) |(?<first>\w)(?<rest>\w+) )

1st Alternative (?<abrev>(?:[A-Z]\.)+)

Group abrev(?<abrev>(?:[A-Z]\.)+)

Non-Capturing Group(?:[A-Z]\.)+

+repeats the group contents below at least once:

Character Class[A-Z]

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

\.the literal . (46₁₀ / 56₈ / 2E₁₆)

2nd Alternative(?<roman>M{0,4}(?:CM|CD|D?C{0,3})(?:XC|XL|L?X{0,3})(?:IX|IV|V?I{0,3}))

Group roman(?<roman>M{0,4}(?:CM|CD|D?C{0,3})(?:XC|XL|L?X{0,3})(?:IX|IV|V?I{0,3}))

M{0,4}the literal M (77₁₀ / 115₈ / 4D₁₆) (case sensitive), repeated between 0 and 4 times

Non-Capturing Group(?:CM|CD|D?C{0,3})

1st AlternativeCM

CMthe literal text CM (case sensitive)

2nd AlternativeCD

CDthe literal text CD (case sensitive)

3rd AlternativeD?C{0,3}

D?optionally matches the literal D (68₁₀ / 104₈ / 44₁₆) (case sensitive)

C{0,3}the literal C (67₁₀ / 103₈ / 43₁₆) (case sensitive), repeated between 0 and 3 times

Non-Capturing Group(?:XC|XL|L?X{0,3})

1st AlternativeXC

XCthe literal text XC (case sensitive)

2nd AlternativeXL

XLthe literal text XL (case sensitive)

3rd AlternativeL?X{0,3}

L?optionally matches the literal L (76₁₀ / 114₈ / 4C₁₆) (case sensitive)

X{0,3}the literal X (88₁₀ / 130₈ / 58₁₆) (case sensitive), repeated between 0 and 3 times

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

3rd Alternative(?<prep>(?i)d?[aoe]s?(?-i))

Group prep(?<prep>(?i)d?[aoe]s?(?-i))

(?i)applies the following effective flags to the remainder of the pattern: gmxui

i modifier: insensitive. Matches without distinguishing uppercase and lowercase letters

d?optionally matches the literal d (100₁₀ / 144₈ / 64₁₆) (case insensitive)

Character Class[aoe]

athe literal a (97₁₀ / 141₈ / 61₁₆) (case insensitive)

othe literal o (111₁₀ / 157₈ / 6F₁₆) (case insensitive)

ethe literal e (101₁₀ / 145₈ / 65₁₆) (case insensitive)

s?optionally matches the literal s (115₁₀ / 163₈ / 73₁₆) (case insensitive)

(?-i)applies the following effective flags to the remainder of the pattern: gmxu

i modifier: -insensitive. Case-sensitive match

4th Alternative(?<first>\w)(?<rest>\w+)

Group first(?<first>\w)

Group rest(?<rest>\w+)

\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

x modifier: extended. Ignores unescaped whitespace and comments outside character classes

u modifier: unicode. Treats the pattern and subject as UTF-16

Search reference

Regular Expression

\b
(
 (?<abrev>(?:[A-Z]\.)+)
 |(?<roman>M{0,4}(?:CM|CD|D?C{0,3})(?:XC|XL|L?X{0,3})(?:IX|IV|V?I{0,3}))
 |(?<prep>(?i)d?[aoe]s?(?-i))
 |(?<first>\w)(?<rest>\w+)
)
\b

Unit Tests

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