REGEX_MATCH for validating date format

[marcin2x4]

I've made a control where end-user inputs date. I want to add a warning that would prompt whenever format is wrong.

The only accepted is "mm/d/yyyy". I tried to built and expression with regex_match but have challenge to combine functions into one solid expression.

[MarqueeCrew]

How about this?

IIF(regex_match([#1],"[01]{0,1}\d\/[0-3]*\d\/20\d{2}"),1,0)

Cheers,

Mark

0 or 1: 0 or 1 occurrences (allows for months 1-9 plus 01-01)

\d: Allows for a second digit in the month

0-3: allows for days starting 00 through 39.

\/ is the / character

20 followed by any 2 numbers

[marcin2x4 · Accepted solution]

I modified the function to allow only one specific format "mm/d/yyyy" and only first day of month.

Also switching the 1,0 arguments at the end of IIF fixed the issue I had that whenever I entered different format alteryx still allowed it to be entered.

Below code works perfectly!

Thanks @MarqueeCrew for your help! I finally made first step in understanding the regexp syntax ;)

IsEmpty([#1])
or 
IIF(regex_match([#1],"(0[1-9]|1[0-2])\/([1]|[12]\d|3[01])\/[12]\d{3}"),0,1)