Regular Expressions 101

Pro

^start of line

Group 1(([1-9]|0[1-9]|1[0-2])\/([1-9]|0[1-9]|1\d|2\d|3[01])\/(19|20)\d{2}|[nN]\/[aA])

1st Alternative([1-9]|0[1-9]|1[0-2])\/([1-9]|0[1-9]|1\d|2\d|3[01])\/(19|20)\d{2}

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

1st Alternative[1-9]

Character Class[1-9]

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

2nd Alternative0[1-9]

0the literal 0 (48₁₀ / 60₈ / 30₁₆)

Character Class[1-9]

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

3rd Alternative1[0-2]

1the literal 1 (49₁₀ / 61₈ / 31₁₆)

Character Class[0-2]

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

\/the literal / (47₁₀ / 57₈ / 2F₁₆)

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

1st Alternative[1-9]

Character Class[1-9]

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

2nd Alternative0[1-9]

0the literal 0 (48₁₀ / 60₈ / 30₁₆)

Character Class[1-9]

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

3rd Alternative1\d

1the literal 1 (49₁₀ / 61₈ / 31₁₆)

\da digit

4th Alternative2\d

2the literal 2 (50₁₀ / 62₈ / 32₁₆)

\da digit

5th 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 / (47₁₀ / 57₈ / 2F₁₆)

Group 4(19|20)

1st Alternative19

19the literal text 19

2nd Alternative20

20the literal text 20

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

2nd Alternative[nN]\/[aA]

Character Class[nN]

nthe literal n (110₁₀ / 156₈ / 6E₁₆) (case sensitive)

Nthe literal N (78₁₀ / 116₈ / 4E₁₆) (case sensitive)

\/the literal / (47₁₀ / 57₈ / 2F₁₆)

Character Class[aA]

athe literal a (97₁₀ / 141₈ / 61₁₆) (case sensitive)

Athe literal A (65₁₀ / 101₈ / 41₁₆) (case sensitive)

$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.

25 tokens

Regular Expression

^(([1-9]|0[1-9]|1[0-2])\/([1-9]|0[1-9]|1\d|2\d|3[01])\/(19|20)\d{2}|[nN]\/[aA])$

New

01/05/2015
1/5/2015
01/5/2015
1/05/2015
n/a
n/A
N/A
N/a

Extraction

01/05/2015
1/5/2015
01/5/2015
1/05/2015
n/a
n/A
N/A
N/a