Regular Expressions 101

^start of line

Group 1(0[1-9]|[12][0-9]|3[01])

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[12][0-9]

Character Class[12]

1the literal 1 (49₁₀ / 61₈ / 31₁₆)

2the literal 2 (50₁₀ / 62₈ / 32₁₆)

Character Class[0-9]

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

3rd Alternative3[01]

3the literal 3 (51₁₀ / 63₈ / 33₁₆)

Character Class[01]

0the literal 0 (48₁₀ / 60₈ / 30₁₆)

1the literal 1 (49₁₀ / 61₈ / 31₁₆)

Group 2(\/|-)?

?repeats the group contents below at most once:

1st Alternative\/

\/the literal / (47₁₀ / 57₈ / 2F₁₆)

2nd Alternative-

-the literal - (45₁₀ / 55₈ / 2D₁₆)

Group 3(0[1-9]|1[012])

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[012]

1the literal 1 (49₁₀ / 61₈ / 31₁₆)

Character Class[012]

0the literal 0 (48₁₀ / 60₈ / 30₁₆)

1the literal 1 (49₁₀ / 61₈ / 31₁₆)

2the literal 2 (50₁₀ / 62₈ / 32₁₆)

Group 4(((\/)?([0-9]{4}|[0-9]{2}))|((\/|-)?[0-9]{4}))

1st Alternative((\/)?([0-9]{4}|[0-9]{2}))

Group 5((\/)?([0-9]{4}|[0-9]{2}))

Group 6(\/)?

?repeats the group contents below at most once:

\/the literal / (47₁₀ / 57₈ / 2F₁₆)

Group 7([0-9]{4}|[0-9]{2})

1st Alternative[0-9]{4}

Character Class[0-9]{4}

{4}matches exactly 4 characters from the set below:

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

2nd Alternative[0-9]{2}

Character Class[0-9]{2}

{2}matches exactly 2 characters from the set below:

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

2nd Alternative((\/|-)?[0-9]{4})

$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

Detailed match information will be displayed here automatically.

Search reference

Regular Expression

^(0[1-9]|[12][0-9]|3[01])(\/|-)?(0[1-9]|1[012])(((\/)?([0-9]{4}|[0-9]{2}))|((\/|-)?[0-9]{4}))$

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Regular Expression

Substitution