Regular Expressions 101

\ban ASCII word boundary

Group 1(0?[1-9]|[12]\d{1}|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{1}

Character Class[12]

1the literal 1 (49₁₀ / 61₈ / 31₁₆)

2the literal 2 (50₁₀ / 62₈ / 32₁₆)

\d{1}a digit, repeated exactly 1 time

3rd Alternative3[01]]

3the literal 3 (51₁₀ / 63₈ / 33₁₆)

Character Class[01]

0the literal 0 (48₁₀ / 60₈ / 30₁₆)

1the literal 1 (49₁₀ / 61₈ / 31₁₆)

]the literal ] (93₁₀ / 135₈ / 5D₁₆)

Character Class[\/|\.|-]

\/the literal / (47₁₀ / 57₈ / 2F₁₆)

|the literal | (124₁₀ / 174₈ / 7C₁₆)

\.the literal . (46₁₀ / 56₈ / 2E₁₆)

|the literal | (124₁₀ / 174₈ / 7C₁₆)

-the literal - (45₁₀ / 55₈ / 2D₁₆)

Group 2(0?[1-9]|12|11)

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 Alternative12

12the literal text 12

3rd Alternative11

11the literal text 11

Character Class[\/|\.|-]

\/the literal / (47₁₀ / 57₈ / 2F₁₆)

|the literal | (124₁₀ / 174₈ / 7C₁₆)

\.the literal . (46₁₀ / 56₈ / 2E₁₆)

|the literal | (124₁₀ / 174₈ / 7C₁₆)

-the literal - (45₁₀ / 55₈ / 2D₁₆)

\d{1,4}a digit, repeated between 1 and 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.

Search reference

Regular Expression

\b(0?[1-9]|[12]\d{1}|3[01]])[\/|\.|-](0?[1-9]|12|11)[\/|\.|-]\d{1,4}\b

Test String
New

Bắt các chuỗi ngày tháng này
12/01/2017
15/2/2017
3/03/2018
12/24/2018
1.1.2018
7-9-18
1.31.2018


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

Test StringNew

ExtractionProcessing...

Test String
New

Extraction
Processing...