Regular Expressions 101

Pro

1st Alternative^0?$

^start of line

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

$end of line

2nd Alternative^(?:0?[1-9]|[12]\d|3[01])(?:-(?:(?:0$|0?[1-9]|1[012]?)(?:-\d{0,4})?)?)?$

^start of line

Non-Capturing Group(?: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)

Non-Capturing Group(?:-(?:(?:0$|0?[1-9]|1[012]?)(?:-\d{0,4})?)?)?

?repeats the group contents below at most once:

-the literal - (45₁₀ / 55₈ / 2D₁₆)

Non-Capturing Group(?:(?:0$|0?[1-9]|1[012]?)(?:-\d{0,4})?)?

?repeats the group contents below at most once:

Non-Capturing Group(?:0$|0?[1-9]|1[012]?)

1st Alternative0$

0the literal 0 (48₁₀ / 60₈ / 30₁₆)

$end of line

2nd 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)

3rd Alternative1[012]?

1the literal 1 (49₁₀ / 61₈ / 31₁₆)

Character Class[012]?

?matches at most one character from the set below:

0the literal 0 (48₁₀ / 60₈ / 30₁₆)

1the literal 1 (49₁₀ / 61₈ / 31₁₆)

2the literal 2 (50₁₀ / 62₈ / 32₁₆)

Non-Capturing Group(?:-\d{0,4})?

?repeats the group contents below at most once:

-the literal - (45₁₀ / 55₈ / 2D₁₆)

\d{0,4}a digit, repeated between 0 and 4 times

$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.

26 tokens

Regular Expression

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

New


30-0
30-01-
30-01-2016
30-01-20161

1-30
01-30-
01-30-2016
01-30-20161

2016-
2016-01-
2016-01-30
2016-01-301

Extraction


30-0
30-01-
30-01-2016
30-01-20161

1-30
01-30-
01-30-2016
01-30-20161

2016-
2016-01-
2016-01-30
2016-01-301