regex101: PCRE2 (PHP) Match Workspace

Pro

^start of line

Negative Lookahead(?![0-9]([0-9](?:\n|(?-1))[0-9]?)$)

Character Class[0-9]

0-9one character from 0 (48₁₀) to 9 (57₁₀)

Group 1([0-9](?:\n|(?-1))[0-9]?)

Character Class[0-9]

0-9one character from 0 (48₁₀) to 9 (57₁₀)

Non-Capturing Group(?:\n|(?-1))

1st Alternative\n

\na line-feed (newline) character (ASCII 10)

2nd Alternative(?-1)

(?-1)calls group 1 as a subroutine

Character Class[0-9]?

?matches at most one character from the set below:

0-9one character from 0 (48₁₀) to 9 (57₁₀)

$end of line

Non-Capturing Group(?:([0-9]*)(?:0\N*(?=\n\2[1-9])|1\N*(?=\n\2[2-9])|2\N*(?=\n\2[3-9])|3\N*(?=\n\2[4-9])|4\N*(?=\n\2[5-9])|5\N*(?=\n\2[6-9])|6\N*(?=\n\2[7-9])|7\N*(?=\n\2[89])|8\N*(?=\n\2[9]))|(?=([0-9](?:\n|(?-1))[0-9])[0-9]))

1st Alternative([0-9]*)(?:0\N*(?=\n\2[1-9])|1\N*(?=\n\2[2-9])|2\N*(?=\n\2[3-9])|3\N*(?=\n\2[4-9])|4\N*(?=\n\2[5-9])|5\N*(?=\n\2[6-9])|6\N*(?=\n\2[7-9])|7\N*(?=\n\2[89])|8\N*(?=\n\2[9]))

Group 2([0-9]*)

Character Class[0-9]*

*matches any number of characters from the set below:

0-9one character from 0 (48₁₀) to 9 (57₁₀)

Non-Capturing Group(?:0\N*(?=\n\2[1-9])|1\N*(?=\n\2[2-9])|2\N*(?=\n\2[3-9])|3\N*(?=\n\2[4-9])|4\N*(?=\n\2[5-9])|5\N*(?=\n\2[6-9])|6\N*(?=\n\2[7-9])|7\N*(?=\n\2[89])|8\N*(?=\n\2[9]))

1st Alternative0\N*(?=\n\2[1-9])

0the literal 0 (48₁₀ / 60₈ / 30₁₆)

\N*any non-newline character, repeated any number of times

Positive Lookahead(?=\n\2[1-9])

\na line-feed (newline) character (ASCII 10)

\2the text saved by group 2

Character Class[1-9]

1-9one character from 1 (49₁₀) to 9 (57₁₀)

2nd Alternative1\N*(?=\n\2[2-9])

1the literal 1 (49₁₀ / 61₈ / 31₁₆)

\N*any non-newline character, repeated any number of times

Positive Lookahead(?=\n\2[2-9])

\na line-feed (newline) character (ASCII 10)

\2the text saved by group 2

Character Class[2-9]

2-9one character from 2 (50₁₀) to 9 (57₁₀)

3rd Alternative2\N*(?=\n\2[3-9])

2the literal 2 (50₁₀ / 62₈ / 32₁₆)

\N*any non-newline character, repeated any number of times

Positive Lookahead(?=\n\2[3-9])

\na line-feed (newline) character (ASCII 10)

\2the text saved by group 2

Character Class[3-9]

3-9one character from 3 (51₁₀) to 9 (57₁₀)

4th Alternative3\N*(?=\n\2[4-9])

3the literal 3 (51₁₀ / 63₈ / 33₁₆)

\N*any non-newline character, repeated any number of times

Positive Lookahead(?=\n\2[4-9])

\na line-feed (newline) character (ASCII 10)

\2the text saved by group 2

Character Class[4-9]

4-9one character from 4 (52₁₀) to 9 (57₁₀)

5th Alternative4\N*(?=\n\2[5-9])

6th Alternative5\N*(?=\n\2[6-9])

7th Alternative6\N*(?=\n\2[7-9])

8th Alternative7\N*(?=\n\2[89])

9th Alternative8\N*(?=\n\2[9])

2nd Alternative(?=([0-9](?:\n|(?-1))[0-9])[0-9])

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

25 tokens

Regular Expression

^(?![0-9]([0-9](?:\n|(?-1))[0-9]?)$)(?:([0-9]*)(?:0\N*(?=\n\2[1-9])|1\N*(?=\n\2[2-9])|2\N*(?=\n\2[3-9])|3\N*(?=\n\2[4-9])|4\N*(?=\n\2[5-9])|5\N*(?=\n\2[6-9])|6\N*(?=\n\2[7-9])|7\N*(?=\n\2[89])|8\N*(?=\n\2[9]))|(?=([0-9](?:\n|(?-1))[0-9])[0-9]))

Unit Tests

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