regex101: JavaScript Match Workspace

\ban ASCII word boundary

Group 1(\d+(-\d+)?|(M{1,4}(CM|CD|D?C{0,3})(XC|XL|L?X{0,3})(IX|IV|V?I{0,3})|M{0,4}(CM|C?D|D?C{1,3})(XC|XL|L?X{0,3})(IX|IV|V?I{0,3})|M{0,4}(CM|CD|D?C{0,3})(XC|X?L|L?X{1,3})(IX|IV|V?I{0,3})|M{0,4}(CM|CD|D?C{0,3})(XC|XL|L?X{0,3})(IX|I?V|V?I{1,3})))

1st Alternative\d+(-\d+)?

\d+a digit, repeated at least once

Group 2(-\d+)?

?repeats the group contents below at most once:

-the literal - (45₁₀ / 55₈ / 2D₁₆)

\d+a digit, repeated at least once

2nd Alternative(M{1,4}(CM|CD|D?C{0,3})(XC|XL|L?X{0,3})(IX|IV|V?I{0,3})|M{0,4}(CM|C?D|D?C{1,3})(XC|XL|L?X{0,3})(IX|IV|V?I{0,3})|M{0,4}(CM|CD|D?C{0,3})(XC|X?L|L?X{1,3})(IX|IV|V?I{0,3})|M{0,4}(CM|CD|D?C{0,3})(XC|XL|L?X{0,3})(IX|I?V|V?I{1,3}))

Group 3(M{1,4}(CM|CD|D?C{0,3})(XC|XL|L?X{0,3})(IX|IV|V?I{0,3})|M{0,4}(CM|C?D|D?C{1,3})(XC|XL|L?X{0,3})(IX|IV|V?I{0,3})|M{0,4}(CM|CD|D?C{0,3})(XC|X?L|L?X{1,3})(IX|IV|V?I{0,3})|M{0,4}(CM|CD|D?C{0,3})(XC|XL|L?X{0,3})(IX|I?V|V?I{1,3}))

1st AlternativeM{1,4}(CM|CD|D?C{0,3})(XC|XL|L?X{0,3})(IX|IV|V?I{0,3})

M{1,4}the literal M (77₁₀ / 115₈ / 4D₁₆) (case sensitive), repeated between 1 and 4 times

Group 4(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

Group 5(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

Group 6(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

2nd AlternativeM{0,4}(CM|C?D|D?C{1,3})(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

Group 7(CM|C?D|D?C{1,3})

1st AlternativeCM

CMthe literal text CM (case sensitive)

2nd AlternativeC?D

C?optionally matches the literal C (67₁₀ / 103₈ / 43₁₆) (case sensitive)

Dthe literal D (68₁₀ / 104₈ / 44₁₆) (case sensitive)

3rd AlternativeD?C{1,3}

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

C{1,3}the literal C (67₁₀ / 103₈ / 43₁₆) (case sensitive), repeated between 1 and 3 times

Group 8(XC|XL|L?X{0,3})

1st AlternativeXC

XCthe literal text XC (case sensitive)

2nd AlternativeXL

3rd AlternativeL?X{0,3}

Group 9(IX|IV|V?I{0,3})

3rd AlternativeM{0,4}(CM|CD|D?C{0,3})(XC|X?L|L?X{1,3})(IX|IV|V?I{0,3})

4th AlternativeM{0,4}(CM|CD|D?C{0,3})(XC|XL|L?X{0,3})(IX|I?V|V?I{1,3})

\ban ASCII 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

Search reference

Regular Expression

\b(\d+(-\d+)?|(M{1,4}(CM|CD|D?C{0,3})(XC|XL|L?X{0,3})(IX|IV|V?I{0,3})|M{0,4}(CM|C?D|D?C{1,3})(XC|XL|L?X{0,3})(IX|IV|V?I{0,3})|M{0,4}(CM|CD|D?C{0,3})(XC|X?L|L?X{1,3})(IX|IV|V?I{0,3})|M{0,4}(CM|CD|D?C{0,3})(XC|XL|L?X{0,3})(IX|I?V|V?I{1,3})))\b

Unit Tests

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