Regular Expressions 101

Pro

^start of string

Group 1(((0[1-9]|[1-2]\d|3[0-1])\/(0[13578]|1[02]))|((0[1-9]|[1-2]\d|30)\/(0[46]|11))|((0[1-9]|1[\d]|2[0-8])\/02))

1st Alternative((0[1-9]|[1-2]\d|3[0-1])\/(0[13578]|1[02]))

Group 2((0[1-9]|[1-2]\d|3[0-1])\/(0[13578]|1[02]))

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

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]\d

Character Class[1-2]

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

\da digit

3rd Alternative3[0-1]

3the literal 3 (51₁₀ / 63₈ / 33₁₆)

Character Class[0-1]

0-1one character from 0 (48₁₀) to 1 (49₁₀)

\/the literal / (47₁₀ / 57₈ / 2F₁₆)

Group 4(0[13578]|1[02])

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 Alternative1[02]

1the literal 1 (49₁₀ / 61₈ / 31₁₆)

Character Class[02]

0the literal 0 (48₁₀ / 60₈ / 30₁₆)

2the literal 2 (50₁₀ / 62₈ / 32₁₆)

2nd Alternative((0[1-9]|[1-2]\d|30)\/(0[46]|11))

Group 5((0[1-9]|[1-2]\d|30)\/(0[46]|11))

Group 6(0[1-9]|[1-2]\d|30)

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]\d

Character Class[1-2]

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

\da digit

3rd Alternative30

30the literal text 30

\/the literal / (47₁₀ / 57₈ / 2F₁₆)

Group 7(0[46]|11)

1st Alternative0[46]

0the literal 0 (48₁₀ / 60₈ / 30₁₆)

Character Class[46]

2nd Alternative11

3rd Alternative((0[1-9]|1[\d]|2[0-8])\/02)

\/the literal / (47₁₀ / 57₈ / 2F₁₆)

Group 10(19|20)

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

$end of string, or before its final line terminator

Global pattern flags

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

Ready to run

25 tokens

Regular Expression

^(((0[1-9]|[1-2]\d|3[0-1])\/(0[13578]|1[02]))|((0[1-9]|[1-2]\d|30)\/(0[46]|11))|((0[1-9]|1[\d]|2[0-8])\/02))\/(19|20)\d{2}$

Regular Expression

Unit Tests