regex101: Date time recognition

1st Alternative^\d{1,2}([ -.\/])(\d{1,2}|[a-zA-z]{3,15})(?1)\d{2,4}( \d{2}:\d{2}(:\d{2}([.:]\d)?)?)?$

^start of line

\d{1,2}a digit, repeated between 1 and 2 times

Group 1([ -.\/])

Character Class[ -.\/]

-.one character from (32₁₀) to . (46₁₀)

\/the literal / (47₁₀ / 57₈ / 2F₁₆)

Group 2(\d{1,2}|[a-zA-z]{3,15})

1st Alternative\d{1,2}

\d{1,2}a digit, repeated between 1 and 2 times

2nd Alternative[a-zA-z]{3,15}

Character Class[a-zA-z]{3,15}

{3,15}matches between 3 and 15 characters from the set below:

a-zone character from a (97₁₀) to z (122₁₀) (case sensitive)

A-zone character from A (65₁₀) to z (122₁₀) (case sensitive)

(?1)calls group 1 as a subroutine

\d{2,4}a digit, repeated between 2 and 4 times

Group 3( \d{2}:\d{2}(:\d{2}([.:]\d)?)?)?

?repeats the group contents below at most once:

the literal (32₁₀ / 40₈ / 20₁₆)

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

:the literal : (58₁₀ / 72₈ / 3A₁₆)

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

Group 4(:\d{2}([.:]\d)?)?

?repeats the group contents below at most once:

:the literal : (58₁₀ / 72₈ / 3A₁₆)

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

Group 5([.:]\d)?

?repeats the group contents below at most once:

Character Class[.:]

.the literal . (46₁₀ / 56₈ / 2E₁₆)

:the literal : (58₁₀ / 72₈ / 3A₁₆)

\da digit

$end of line

2nd Alternative^(\d{1,2}|[a-zA-z]{3,15})([ -.\/])\d{1,2}(?7)\d{2,4}( \d{2}:\d{2}(:\d{2}([.:]\d)?)?)?$

^start of line

Group 6(\d{1,2}|[a-zA-z]{3,15})

1st Alternative\d{1,2}

\d{1,2}a digit, repeated between 1 and 2 times

2nd Alternative[a-zA-z]{3,15}

Character Class[a-zA-z]{3,15}

{3,15}matches between 3 and 15 characters from the set below:

a-zone character from a (97₁₀) to z (122₁₀) (case sensitive)

A-zone character from A (65₁₀) to z (122₁₀) (case sensitive)

Group 7([ -.\/])

Character Class[ -.\/]

-.one character from (32₁₀) to . (46₁₀)

\/the literal / (47₁₀ / 57₈ / 2F₁₆)

\d{1,2}a digit, repeated between 1 and 2 times

(?7)calls group 7 as a subroutine

\d{2,4}a digit, repeated between 2 and 4 times

Group 8( \d{2}:\d{2}(:\d{2}([.:]\d)?)?)?

?repeats the group contents below at most once:

the literal (32₁₀ / 40₈ / 20₁₆)

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

:the literal : (58₁₀ / 72₈ / 3A₁₆)

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

Group 9(:\d{2}([.:]\d)?)?

?repeats the group contents below at most once:

:the literal : (58₁₀ / 72₈ / 3A₁₆)

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

Group 10([.:]\d)?

?repeats the group contents below at most once:

Character Class[.:]

.the literal . (46₁₀ / 56₈ / 2E₁₆)

:the literal : (58₁₀ / 72₈ / 3A₁₆)

\da digit

$end of line

3rd Alternative^\d{2,4}([ -.\/])(\d{1,2}|[a-zA-z]{3,15})\d{1,2}(?11)( \d{2}:\d{2}(:\d{2}([.:]\d)?)?)?$

^start of line

\d{2,4}a digit, repeated between 2 and 4 times

Group 11([ -.\/])

Character Class[ -.\/]

-.one character from (32₁₀) to . (46₁₀)

\/the literal / (47₁₀ / 57₈ / 2F₁₆)

Group 12(\d{1,2}|[a-zA-z]{3,15})

\d{1,2}a digit, repeated between 1 and 2 times

(?11)calls group 11 as a subroutine

Group 13( \d{2}:\d{2}(:\d{2}([.:]\d)?)?)?

$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

Search reference

Regular Expression

^\d{1,2}([ -.\/])(\d{1,2}|[a-zA-z]{3,15})(?1)\d{2,4}( \d{2}:\d{2}(:\d{2}([.:]\d)?)?)?$|^(\d{1,2}|[a-zA-z]{3,15})([ -.\/])\d{1,2}(?7)\d{2,4}( \d{2}:\d{2}(:\d{2}([.:]\d)?)?)?$|^\d{2,4}([ -.\/])(\d{1,2}|[a-zA-z]{3,15})\d{1,2}(?11)( \d{2}:\d{2}(:\d{2}([.:]\d)?)?)?$

New

23/02/1993
23-02/1993
23-fev-1993
fev-23-1993
fev.02.93
28-OCT-90
28-OCT-1990
10/28/90
10/28/1990
28.10.90
dd.mm.yyyy
28.10.1990
90/10/28
yyyy/mm/dd
1990/10/28
4 Q 1990
OCT 90
OCT 1990
01:02
01:02:34.75
02:34
02:34.75
20 08:03
20 08:03:00
20-JUN-1990 08:03
20-JUN-1990 08:03:00
1990-06-20 08:03
1990-06-20 08:03:00.0