Regular Expressions 101

\ban ASCII word boundary

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

1st Alternative0?[1-9]

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

Character Class[1-9]

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

2nd Alternative[12]\d

Character Class[12]

1the literal 1 (49₁₀ / 61₈ / 31₁₆)

2the literal 2 (50₁₀ / 62₈ / 32₁₆)

\da digit

3rd Alternative3[01]

3the literal 3 (51₁₀ / 63₈ / 33₁₆)

Character Class[01]

0the literal 0 (48₁₀ / 60₈ / 30₁₆)

1the literal 1 (49₁₀ / 61₈ / 31₁₆)

Character Class[\/\-.]

\/the literal / (47₁₀ / 57₈ / 2F₁₆)

\-the literal - (45₁₀ / 55₈ / 2D₁₆)

.the literal . (46₁₀ / 56₈ / 2E₁₆)

Group 2(0?[1-9]|[12]\d|3[01])

1st Alternative0?[1-9]

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

Character Class[1-9]

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

2nd Alternative[12]\d

Character Class[12]

1the literal 1 (49₁₀ / 61₈ / 31₁₆)

2the literal 2 (50₁₀ / 62₈ / 32₁₆)

\da digit

3rd Alternative3[01]

3the literal 3 (51₁₀ / 63₈ / 33₁₆)

Character Class[01]

0the literal 0 (48₁₀ / 60₈ / 30₁₆)

1the literal 1 (49₁₀ / 61₈ / 31₁₆)

Character Class[\/\-.]

\/the literal / (47₁₀ / 57₈ / 2F₁₆)

\-the literal - (45₁₀ / 55₈ / 2D₁₆)

.the literal . (46₁₀ / 56₈ / 2E₁₆)

Group 3(\d{2}|\d{4})

1st Alternative\d{2}

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

2nd Alternative\d{4}

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

\ban ASCII word boundary

Global pattern flags

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

Detailed match information will be displayed here automatically.

25 tokens

Regular Expression

\b(0?[1-9]|[12]\d|3[01])[\/\-.](0?[1-9]|[12]\d|3[01])[\/\-.](\d{2}|\d{4})\b

New

Bắt các chuỗi ngày tháng này
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Không bắt các chuỗi như thế này, vì không đúng ngày tháng
123/2/1234  13/ab/3346  12/223/12 60/60/2018 32/12/2018

Regular Expression

Extraction