Regular Expressions 101

Explanation
Pro

^start of string

Group 1((19\d{2})|(20\d{2}))

1st Alternative(19\d{2})

Group 2(19\d{2})

19the literal text 19

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

2nd Alternative(20\d{2})

Group 3(20\d{2})

20the literal text 20

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

-the literal - (45₁₀ / 55₈ / 2D₁₆)

Group 4(((02)-(0[1-9]|[1-2][0-9]))|(((0(1|[3-9]))|(1[0-2]))-(0[1-9]|[1-2][0-9]|30))|((01|03|05|07|08|10|12)-(31)))

1st Alternative((02)-(0[1-9]|[1-2][0-9]))

Group 5((02)-(0[1-9]|[1-2][0-9]))

Group 6(02)

02the literal text 02

-the literal - (45₁₀ / 55₈ / 2D₁₆)

Group 7(0[1-9]|[1-2][0-9])

1st Alternative0[1-9]

0the literal 0 (48₁₀ / 60₈ / 30₁₆)

Character Class[1-9]

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

2nd Alternative[1-2][0-9]

Character Class[1-2]

1-2one character from 1 (49₁₀) to 2 (50₁₀)

Character Class[0-9]

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

2nd Alternative(((0(1|[3-9]))|(1[0-2]))-(0[1-9]|[1-2][0-9]|30))

Group 8(((0(1|[3-9]))|(1[0-2]))-(0[1-9]|[1-2][0-9]|30))

Group 9((0(1|[3-9]))|(1[0-2]))

1st Alternative(0(1|[3-9]))

Group 10(0(1|[3-9]))

0the literal 0 (48₁₀ / 60₈ / 30₁₆)

Group 11(1|[3-9])

1st Alternative1

1the literal 1 (49₁₀ / 61₈ / 31₁₆)

2nd Alternative[3-9]

Character Class[3-9]

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

2nd Alternative(1[0-2])

Group 12(1[0-2])

-the literal - (45₁₀ / 55₈ / 2D₁₆)

Group 13(0[1-9]|[1-2][0-9]|30)

3rd Alternative((01|03|05|07|08|10|12)-(31))

$end of string, or before its final line terminator

Match Information

Detailed match information will be displayed here automatically.

Quick Reference

25 tokens

Regular Expression

^((19\d{2})|(20\d{2}))-(((02)-(0[1-9]|[1-2][0-9]))|(((0(1|[3-9]))|(1[0-2]))-(0[1-9]|[1-2][0-9]|30))|((01|03|05|07|08|10|12)-(31)))$

2000-12-31

Extraction

2000-12-31