Regular Expressions 101

Explanation

Pro

Group 1((?:\d[-–_ \.]*){4,5}|(?:\d[-–_ \.]*){8})

1st Alternative(?:\d[-–_ \.]*){4,5}

Non-Capturing Group(?:\d[-–_ \.]*){4,5}

{4,5}repeats the group contents below between 4 and 5 times:

\da digit

Character Class[-–_ \.]*

*matches any number of characters from the set below:

-the literal - (45₁₀ / 55₈ / 2D₁₆)

–the literal – (8211₁₀ / 20023₈ / 2013₁₆)

_the literal _ (95₁₀ / 137₈ / 5F₁₆)

the literal (32₁₀ / 40₈ / 20₁₆)

\.the literal . (46₁₀ / 56₈ / 2E₁₆)

2nd Alternative(?:\d[-–_ \.]*){8}

Non-Capturing Group(?:\d[-–_ \.]*){8}

{8}repeats the group contents below exactly 8 times:

\da digit

Character Class[-–_ \.]*

*matches any number of characters from the set below:

-the literal - (45₁₀ / 55₈ / 2D₁₆)

–the literal – (8211₁₀ / 20023₈ / 2013₁₆)

_the literal _ (95₁₀ / 137₈ / 5F₁₆)

the literal (32₁₀ / 40₈ / 20₁₆)

\.the literal . (46₁₀ / 56₈ / 2E₁₆)

Non-Capturing Group(?:\d[-–_ \.]*){4}

{4}repeats the group contents below exactly 4 times:

\da digit

Character Class[-–_ \.]*

*matches any number of characters from the set below:

-the literal - (45₁₀ / 55₈ / 2D₁₆)

–the literal – (8211₁₀ / 20023₈ / 2013₁₆)

_the literal _ (95₁₀ / 137₈ / 5F₁₆)

the literal (32₁₀ / 40₈ / 20₁₆)

\.the literal . (46₁₀ / 56₈ / 2E₁₆)

$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

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

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25 tokens

((?:\d[-–_ \.]*){4,5}|(?:\d[-–_ \.]*){8})(?:\d[-–_ \.]*){4}$

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