Regular Expressions 101

Explanation
Pro

1st Alternative(\d?\/?)(\d+[A-z]?\s)_([A-z]\S+)(?=\s)(\s.+)

Group 1(\d?\/?)

\d?optionally matches a Unicode decimal digit

\/?optionally matches the literal / (47₁₀ / 57₈ / 2F₁₆)

Group 2(\d+[A-z]?\s)

\d+a Unicode decimal digit, repeated at least once

Character Class[A-z]?

?matches at most one character from the set below:

A-zone character from A (65₁₀) to z (122₁₀) (case sensitive)

\sa Unicode whitespace character

_the literal _ (95₁₀ / 137₈ / 5F₁₆)

Group 3([A-z]\S+)

Character Class[A-z]

A-zone character from A (65₁₀) to z (122₁₀) (case sensitive)

\S+any character that is not Unicode whitespace, repeated at least once

Positive Lookahead(?=\s)

\sa Unicode whitespace character

Group 4(\s.+)

\sa Unicode whitespace character

.+any Unicode character (except for line terminators), repeated at least once

2nd Alternative(\d+[A-z]?)(\d+[A-z]?\s)_([A-z]\S+)(?=\s)(\s.+)

Group 5(\d+[A-z]?)

\d+a Unicode decimal digit, repeated at least once

Character Class[A-z]?

?matches at most one character from the set below:

A-zone character from A (65₁₀) to z (122₁₀) (case sensitive)

Group 6(\d+[A-z]?\s)

\d+a Unicode decimal digit, repeated at least once

Character Class[A-z]?

?matches at most one character from the set below:

A-zone character from A (65₁₀) to z (122₁₀) (case sensitive)

\sa Unicode whitespace character

_the literal _ (95₁₀ / 137₈ / 5F₁₆)

Group 7([A-z]\S+)

Character Class[A-z]

A-zone character from A (65₁₀) to z (122₁₀) (case sensitive)

\S+any character that is not Unicode whitespace, repeated at least once

Positive Lookahead(?=\s)

\sa Unicode whitespace character

Group 8(\s.+)

\sa Unicode whitespace character

.+any Unicode character (except for line terminators), repeated at least once

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

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Quick Reference

25 tokens

Regular Expression

(\d?\/?)(\d+[A-z]?\s)_([A-z]\S+)(?=\s)(\s.+)|(\d+[A-z]?)(\d+[A-z]?\s)_([A-z]\S+)(?=\s)(\s.+)

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