Regular Expressions 101

Explanation

Pro

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

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

Character Class[0-2]

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

Character Class[0-9]

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

2nd Alternative3[0-1]

3the literal 3 (51₁₀ / 63₈ / 33₁₆)

Character Class[0-1]

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

\-the literal - (45₁₀ / 55₈ / 2D₁₆)

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

1st Alternative0[1-9]

0the literal 0 (48₁₀ / 60₈ / 30₁₆)

Character Class[1-9]

1-9one character from 1 (49₁₀) 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)

\-the literal - (45₁₀ / 55₈ / 2D₁₆)

\d{4}a digit, repeated exactly 4 times

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

Detailed match information will be displayed here automatically.

25 tokens

([0-2][0-9]|3[0-1])\-(0[1-9]|1[0-2])\-\d{4}

New

31-12-1999 
31-13-1999

31-12-1999 
31-13-1999