Regular Expressions 101

Explanation

Pro

1st Alternative^(?:(?:(?:0?[13578]|1[02])(\/)31)\1|(?:(?:0?[1,3-9]|1[0-2])(\/)(?:29|30)\2))(?:(?:19|[2-9]\d)\d{2})$

^start of line

Non-Capturing Group(?:(?:(?:0?[13578]|1[02])(\/)31)\1|(?:(?:0?[1,3-9]|1[0-2])(\/)(?:29|30)\2))

1st Alternative(?:(?:0?[13578]|1[02])(\/)31)\1

Non-Capturing Group(?:(?:0?[13578]|1[02])(\/)31)

Non-Capturing Group(?:0?[13578]|1[02])

1st Alternative0?[13578]

0?optionally matches the 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 Alternative1[02]

1the literal 1 (49₁₀ / 61₈ / 31₁₆)

Character Class[02]

0the literal 0 (48₁₀ / 60₈ / 30₁₆)

2the literal 2 (50₁₀ / 62₈ / 32₁₆)

Group 1(\/)

\/the literal / (47₁₀ / 57₈ / 2F₁₆)

31the literal text 31

\1the text saved by group 1

2nd Alternative(?:(?:0?[1,3-9]|1[0-2])(\/)(?:29|30)\2)

Non-Capturing Group(?:(?:0?[1,3-9]|1[0-2])(\/)(?:29|30)\2)

Non-Capturing Group(?:0?[1,3-9]|1[0-2])

1st Alternative0?[1,3-9]

0?optionally matches the literal 0 (48₁₀ / 60₈ / 30₁₆)

Character Class[1,3-9]

1the literal 1 (49₁₀ / 61₈ / 31₁₆)

,the literal , (44₁₀ / 54₈ / 2C₁₆)

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

2nd Alternative1[0-2]

1the literal 1 (49₁₀ / 61₈ / 31₁₆)

Character Class[0-2]

0-2one character from 0 (48₁₀) to 2 (50₁₀)

Group 2(\/)

\/the literal / (47₁₀ / 57₈ / 2F₁₆)

Non-Capturing Group(?:29|30)

1st Alternative29

29the literal text 29

2nd Alternative30

30the literal text 30

\2the text saved by group 2

Non-Capturing Group(?:(?:19|[2-9]\d)\d{2})

Non-Capturing Group(?:19|[2-9]\d)

1st Alternative19

19the literal text 19

2nd Alternative[2-9]\d

Character Class[2-9]

\da digit

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

$end of line

2nd Alternative^(?:0?2(\/)29\3(?:(?:(?:19|20)(?:0[048]|[2468][048]|[13579][26]))))$

3rd Alternative^(?:(?:0?[1-9])|(?:1[0-2]))(\/)(?:0?[1-9]|1\d|2[0-8])\4(?:(?:19|[0-9]\d)?\d{2})$

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

Match Information

Detailed match information will be displayed here automatically.

Quick Reference

25 tokens

Regular Expression

^(?:(?:(?:0?[13578]|1[02])(\/)31)\1|(?:(?:0?[1,3-9]|1[0-2])(\/)(?:29|30)\2))(?:(?:19|[2-9]\d)\d{2})$|^(?:0?2(\/)29\3(?:(?:(?:19|20)(?:0[048]|[2468][048]|[13579][26]))))$|^(?:(?:0?[1-9])|(?:1[0-2]))(\/)(?:0?[1-9]|1\d|2[0-8])\4(?:(?:19|[0-9]\d)?\d{2})$

1/1/2019
2/29/2020
1/31/00
2/29/2000
3/31/2019
2/29/2020
7/23/1999
7/31/1999
7/28/1999
7/21/1999
7/5/1964
7/21/2000
2/29/1900
6/5/1999
5/5/1999
4/4/1999
3/3/1999
2/2/1999
2/29/1996
2/29/2000
1/1/1954
1/1/1985
3/31/2019
1/29/2010
10/21/1967