Regex to match month name followed by year

Question

Is it possible to use a regex to match "February 2009", for example?

The restrictions are January - December, followed by 1990 - 2010. Fortunately, non-english isn't a concern. — Jeremy, Apr 16 '10 at 19:08
*followed by 1990 - 2010* — Is it intentional to have this tight upper limit? There's only 8 months left to 2011. — kennytm, Apr 16 '10 at 19:16

score 59 · Accepted Answer · answered Apr 16 '10 at 19:08

Along the lines of

\b(?:Jan(?:uary)?|Feb(?:ruary)?|...|Dec(?:ember)?) (?:19[7-9]\d|2\d{3})(?=\D|$)

that's

\b                  # a word boundary
(?:                 # non-capturing group
  Jan(?:uary)?      # Jan(uary)
  |Feb(?:ruary)?    #
  |...              # and so on
  |Dec(?:ember)?    # Dec(ember)
)                   # end group
                    # a space
(?:                 # non-capturing group
  19[7-9]\d|2\d{3}  # 1970-2999
)                   # end group
(?=\D|$)            # followed by: anything but a digit or the end of string

OBTW, 1990-2010 is `(?:199\d|20[01]\d)` – Tomalak Apr 16 '10 at 19:19 — Tomalak, Apr 16 '10 at 19:19

score 33 · Answer 2 · answered Jul 11 '14 at 07:25

33

I had to work on this to match a few fringe examples, but I ended up using

(\b\d{1,2}\D{0,3})?\b(?:Jan(?:uary)?|Feb(?:ruary)?|Mar(?:ch)?|Apr(?:il)?|May|Jun(?:e)?|Jul(?:y)?|Aug(?:ust)?|Sep(?:tember)?|Oct(?:ober)?|(Nov|Dec)(?:ember)?)\D?(\d{1,2}\D?)?\D?((19[7-9]\d|20\d{2})|\d{2})

to capture dates with word months in them

answered Jul 11 '14 at 07:25

Beerswiller

659
6
8

4

Just a minor thing, for the months instead of (Nov|Dec) it should be (?:Nov|Dec), or at least I had to change that in order for it to work with Python otherwise it was returning an empty [''] match – Walter R Aug 03 '17 at 19:04
You can add (?i)(regex_part_to_make_case_insensitive) or (?i)regex_part_to_make_case_insensitive(?-i) depending on the regex processor you are using. – Onyr Apr 22 '21 at 16:04

Pedro Machin · Answer 3 · 2018-01-31T14:01:02.507

4

Modifying Beerswiller's answer, if you want "st"/"nd"/"rd" variations:

(\b\d{1,2}\D{0,3})?\b(?:Jan(?:uary)?|Feb(?:ruary)?|Mar(?:ch)?|Apr(?:il)?|May|Jun(?:e)?|Jul(?:y)?|Aug(?:ust)?|Sep(?:tember)?|Oct(?:ober)?|(Nov|Dec)(?:ember)?)\D?(\d{1,2}(st|nd|rd|th)?)?(([,.\-\/])\D?)?((19[7-9]\d|20\d{2})|\d{2})*

edited Jan 31 '18 at 14:01

answered Jan 31 '18 at 13:28

Pedro Machin

51
3

It also passes 34rth July 1999 as a valid date! – Zujaj Misbah Khan Oct 20 '20 at 06:24
@ZujajMisbahKhan it is not possible to make all mathematical calculations in a regular expression to see which months have 28, 29, 30 or 31, also depending on whether the year is odd or not. For this you can take the resulting matched date and validate it with you language of choice functions. – Alex P. May 10 '23 at 18:05

score 3 · Answer 4 · edited Sep 06 '18 at 15:44

3

This regex accounts for some spacing around the comma.

Sometimes it's not always in the right place.

((\b\d{1,2}\D{0,3})?\b(?:Jan(?:uary)?|Feb(?:ruary)?|Mar(?:ch)?|Apr(?:il)?|May|Jun(?:e)?|Jul(?:y)?|Aug(?:ust)?|Sep(?:tember)?|Oct(?:ober)?|(Nov|Dec)(?:ember)?)\D?)(\d{1,2}(st|nd|rd|th)?)?((\s*[,.\-\/]\s*)\D?)?\s*((19[0-9]\d|20\d{2})|\d{2})*

edited Sep 06 '18 at 15:44

Acapulco

3,373
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answered Sep 06 '18 at 14:49

Todd

41
1

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I would suggest `Sep(?:t(?:ember)?)?`. I've seen Sept used in numerous datasets. – Sancarn Jun 08 '23 at 09:09

score 0 · Answer 5 · edited Aug 25 '23 at 19:38

The regex below will take into account the max number of days for the relevant month and also take into account leap years for February.

^(((0[1-9]|[12][0-9]|3[01])[ ]\b(?:Jan(?:uary)?|Mar(?:ch)?|May|Jul(?:y)?|Aug(?:ust)?|Oct(?:ober)?|Dec(?:ember)?)|(0[1-9]|[12][0-9]|30)[ ]\b(?:Apr(?:il)?|Jun(?:e)?|Sep(?:tember)?|Nov(?:ember)?)|(0[1-9]|1\d|2[0-8])[ ]\b(?:Feb(?:ruary)?))[ ]\d{4}|29[ ]\b(?:Feb(?:ruary)?)[ ](\d{2}(0[48]|[2468][048]|[13579][26])|([02468][048]|[1359][26])00))$

Regex to match month name followed by year

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