regex101: PCRE (Legacy) Match Workspace

Definition Group(?(DEFINE)(?<cons>\b(?: (?<x>\d*) (?:(?<a0>0)|(?<a1>1)|(?<a2>2)|(?<a3>3)|(?<a4>4) |(?<a5>5)|(?<a6>6)|(?<a7>7)|(?<a8>8)) (?<y> ,\g{x} (?(a0)1)(?(a1)2)(?(a2)3)(?(a3)4)(?(a4)5) (?(a5)6)(?(a6)7)(?(a7)8)(?(a8)9) | 9 (?&y) 0 ) # handle the 999 => 1000 case separately | (?<z> 9,10 | 9(?&z)0 ) )\b))

Group cons(?<cons>\b(?: (?<x>\d*) (?:(?<a0>0)|(?<a1>1)|(?<a2>2)|(?<a3>3)|(?<a4>4) |(?<a5>5)|(?<a6>6)|(?<a7>7)|(?<a8>8)) (?<y> ,\g{x} (?(a0)1)(?(a1)2)(?(a2)3)(?(a3)4)(?(a4)5) (?(a5)6)(?(a6)7)(?(a7)8)(?(a8)9) | 9 (?&y) 0 ) # handle the 999 => 1000 case separately | (?<z> 9,10 | 9(?&z)0 ) )\b)

\ban ASCII word boundary

Non-Capturing Group(?: (?<x>\d*) (?:(?<a0>0)|(?<a1>1)|(?<a2>2)|(?<a3>3)|(?<a4>4) |(?<a5>5)|(?<a6>6)|(?<a7>7)|(?<a8>8)) (?<y> ,\g{x} (?(a0)1)(?(a1)2)(?(a2)3)(?(a3)4)(?(a4)5) (?(a5)6)(?(a6)7)(?(a7)8)(?(a8)9) | 9 (?&y) 0 ) # handle the 999 => 1000 case separately | (?<z> 9,10 | 9(?&z)0 ) )

1st Alternative (?<x>\d*) (?:(?<a0>0)|(?<a1>1)|(?<a2>2)|(?<a3>3)|(?<a4>4) |(?<a5>5)|(?<a6>6)|(?<a7>7)|(?<a8>8)) (?<y> ,\g{x} (?(a0)1)(?(a1)2)(?(a2)3)(?(a3)4)(?(a4)5) (?(a5)6)(?(a6)7)(?(a7)8)(?(a8)9) | 9 (?&y) 0 ) # handle the 999 => 1000 case separately

Group x(?<x>\d*)

\d*a digit, repeated any number of times

Non-Capturing Group(?:(?<a0>0)|(?<a1>1)|(?<a2>2)|(?<a3>3)|(?<a4>4) |(?<a5>5)|(?<a6>6)|(?<a7>7)|(?<a8>8))

1st Alternative(?<a0>0)

Group a0(?<a0>0)

0the literal 0 (48₁₀ / 60₈ / 30₁₆)

2nd Alternative(?<a1>1)

Group a1(?<a1>1)

1the literal 1 (49₁₀ / 61₈ / 31₁₆)

3rd Alternative(?<a2>2)

Group a2(?<a2>2)

2the literal 2 (50₁₀ / 62₈ / 32₁₆)

4th Alternative(?<a3>3)

Group a3(?<a3>3)

3the literal 3 (51₁₀ / 63₈ / 33₁₆)

5th Alternative(?<a4>4)

Group a4(?<a4>4)

4the literal 4 (52₁₀ / 64₈ / 34₁₆)

6th Alternative(?<a5>5)

Group a5(?<a5>5)

5the literal 5 (53₁₀ / 65₈ / 35₁₆)

7th Alternative(?<a6>6)

Group a6(?<a6>6)

6the literal 6 (54₁₀ / 66₈ / 36₁₆)

8th Alternative(?<a7>7)

Group a7(?<a7>7)

7the literal 7 (55₁₀ / 67₈ / 37₁₆)

9th Alternative(?<a8>8)

Group a8(?<a8>8)

8the literal 8 (56₁₀ / 70₈ / 38₁₆)

Group y(?<y> ,\g{x} (?(a0)1)(?(a1)2)(?(a2)3)(?(a3)4)(?(a4)5) (?(a5)6)(?(a6)7)(?(a7)8)(?(a8)9) | 9 (?&y) 0 )

1st Alternative ,\g{x} (?(a0)1)(?(a1)2)(?(a2)3)(?(a3)4)(?(a4)5) (?(a5)6)(?(a6)7)(?(a7)8)(?(a8)9)

2nd Alternative 9 (?&y) 0

Comment: handle the 999 => 1000 case separately

2nd Alternative (?<z> 9,10 | 9(?&z)0 )

\ban ASCII word boundary

Comment: list of two or more consecutive integers

Positive Lookahead(?=(?&cons))

\d+a digit, repeated at least once

Non-Capturing Group(?:,(?=(?&cons))\d+)*

,the literal text ,

\d+a digit, repeated at least once

Global pattern flags

g modifier: global. Finds all matches instead of stopping after the first

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

25 tokens

Regular Expression

(?(DEFINE)(?<cons>\b(?:
    (?<x>\d*)
    (?:(?<a0>0)|(?<a1>1)|(?<a2>2)|(?<a3>3)|(?<a4>4)
               |(?<a5>5)|(?<a6>6)|(?<a7>7)|(?<a8>8))
    (?<y>
        ,\g{x}
        (?(a0)1)(?(a1)2)(?(a2)3)(?(a3)4)(?(a4)5)
        (?(a5)6)(?(a6)7)(?(a7)8)(?(a8)9)
      | 9 (?&y) 0
    )
    # handle the 999 => 1000 case separately
  | (?<z> 9,10 | 9(?&z)0 )
)\b))

# list of two or more consecutive integers
(?=(?&cons))\d+
(?:,(?=(?&cons))\d+)*
,\d+

New

0,1,2,3
8,9,10,11
1999,2000,2001
99,100,101

42
3,2,1
1,2,4
10,11,13

Substitution

0,1,2,3
8,9,10,11
1999,2000,2001
99,100,101

42
3,2,1
1,2,4
10,11,13