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THE_BLUE's avatar
THE_BLUE
Icon for Cirrostratus rankCirrostratus
Nov 04, 2021

Parameter Value - Regular Expression

I want to restrict parameter value to accept date only, is below Regular Expression will work? ^([0-2][0-9]|(3)[0-1])(\/)(((0)[0-9])|((1)[0-2]))(\/)\d{4}$
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  • Daniel_Wolf's avatar
    Daniel_Wolf
    Nov 05, 2021

    I found this regex, fits in the 254 character limit and checks:

    1. valid dates
    2. if leap year, then 29.2. is also valid
    (^(((0[1-9]|1[0-9]|2[0-8])[\/](0[1-9]|1[012]))|((29|30|31)[\/](0[13578]|1[02]))|((29|30)[\/](0[4,6,9]|11)))[\/](19|[2-9][0-9])\d\d$)|(^29[\/]02[\/](19|[2-9][0-9])(00|04|08|12|16|20|24|28|32|36|40|44|48|52|56|60|64|68|72|76|80|84|88|92|96)$)
THE_BLUE's avatar
THE_BLUE
Icon for Cirrostratus rankCirrostratus
Nov 05, 2021

i have modified the regex to ^([0-2][0-9]|(3)[0-1])(\/)(([0-9]|(0)[0-9])|((1)[0-2]))(\/)\d{4}$ , now it can accept both 29/3/2026 and 02/03/2022 but again can't detect non-existing date ex 31/2/2021

  • Daniel_Wolf's avatar
    Daniel_Wolf
    Icon for MVP rankMVP
    Nov 05, 2021

    I cannot judge which regex meets your requirements best. The usual syntax is dd/mm/yyyy.

    Is it more important for you, to have a syntax that would catch dd/mm/yyyy and dd/m/yyyy?

    Or is it it more important to filter out non-existing dates like 31/02/2022 and stick to the defacto standard of dd/mm/yyyy?

     

    My regex foo is not strong enough to combine both requirements into one single regex.