regex101: Java Match Workspace

^start of line

Positive Lookahead(?=\d+(?:/\d+/\d+)?$)

\d+a digit, repeated at least once

Non-Capturing Group(?:/\d+/\d+)?

?repeats the group contents below at most once:

/the literal / (47₁₀ / 57₈ / 2F₁₆)

\d+a digit, repeated at least once

/the literal / (47₁₀ / 57₈ / 2F₁₆)

\d+a digit, repeated at least once

$end of line

Non-Capturing Group(?:02/?(?:[01]\d|2\d)/?(?:19|20)(?:0[048]|[13579][26]|[2468][048])|(?:0[13578]|10|12)/?(?:[0-2]\d|3[01])/?(?:19|20)\d{2}|(?:0[469]|11)/?(?:[0-2]\d|30)/?(?:19|20)\d{2}|02/?(?:[0-1]\d|2[0-8])\?(?:19|20)\d{2})

1st Alternative02/?(?:[01]\d|2\d)/?(?:19|20)(?:0[048]|[13579][26]|[2468][048])

02the literal text 02

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

Non-Capturing Group(?:[01]\d|2\d)

1st Alternative[01]\d

Character Class[01]

0the literal 0 (48₁₀ / 60₈ / 30₁₆)

1the literal 1 (49₁₀ / 61₈ / 31₁₆)

\da digit

2nd Alternative2\d

2the literal 2 (50₁₀ / 62₈ / 32₁₆)

\da digit

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

Non-Capturing Group(?:19|20)

1st Alternative19

19the literal text 19

2nd Alternative20

20the literal text 20

Non-Capturing Group(?:0[048]|[13579][26]|[2468][048])

1st Alternative0[048]

0the literal 0 (48₁₀ / 60₈ / 30₁₆)

Character Class[048]

0the literal 0 (48₁₀ / 60₈ / 30₁₆)

4the literal 4 (52₁₀ / 64₈ / 34₁₆)

8the literal 8 (56₁₀ / 70₈ / 38₁₆)

2nd Alternative[13579][26]

Character Class[13579]

1the literal 1 (49₁₀ / 61₈ / 31₁₆)

3the literal 3 (51₁₀ / 63₈ / 33₁₆)

5the literal 5 (53₁₀ / 65₈ / 35₁₆)

7the literal 7 (55₁₀ / 67₈ / 37₁₆)

9the literal 9 (57₁₀ / 71₈ / 39₁₆)

Character Class[26]

2the literal 2 (50₁₀ / 62₈ / 32₁₆)

6the literal 6 (54₁₀ / 66₈ / 36₁₆)

3rd Alternative[2468][048]

Character Class[2468]

2the literal 2 (50₁₀ / 62₈ / 32₁₆)

4the literal 4 (52₁₀ / 64₈ / 34₁₆)

6the literal 6 (54₁₀ / 66₈ / 36₁₆)

8the literal 8 (56₁₀ / 70₈ / 38₁₆)

Character Class[048]

0the literal 0 (48₁₀ / 60₈ / 30₁₆)

4the literal 4 (52₁₀ / 64₈ / 34₁₆)

8the literal 8 (56₁₀ / 70₈ / 38₁₆)

2nd Alternative(?:0[13578]|10|12)/?(?:[0-2]\d|3[01])/?(?:19|20)\d{2}

Non-Capturing Group(?:0[13578]|10|12)

1st Alternative0[13578]

0the literal 0 (48₁₀ / 60₈ / 30₁₆)

Character Class[13578]

1the literal 1 (49₁₀ / 61₈ / 31₁₆)

3the literal 3 (51₁₀ / 63₈ / 33₁₆)

5the literal 5 (53₁₀ / 65₈ / 35₁₆)

7the literal 7 (55₁₀ / 67₈ / 37₁₆)

8the literal 8 (56₁₀ / 70₈ / 38₁₆)

2nd Alternative10

10the literal text 10

3rd Alternative12

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

Non-Capturing Group(?:[0-2]\d|3[01])

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

Non-Capturing Group(?:19|20)

\d{2}a digit, repeated exactly 2 times

3rd Alternative(?:0[469]|11)/?(?:[0-2]\d|30)/?(?:19|20)\d{2}

4th Alternative02/?(?:[0-1]\d|2[0-8])\?(?:19|20)\d{2}

$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

Search reference

Regular Expression

^(?=\d+(?:/\d+/\d+)?$)(?:02/?(?:[01]\d|2\d)/?(?:19|20)(?:0[048]|[13579][26]|[2468][048])|(?:0[13578]|10|12)/?(?:[0-2]\d|3[01])/?(?:19|20)\d{2}|(?:0[469]|11)/?(?:[0-2]\d|30)/?(?:19|20)\d{2}|02/?(?:[0-1]\d|2[0-8])\?(?:19|20)\d{2})$

New