What is the best way to validate the first 8 chars of a file name is a valid date of form YYYYMMDD please?
%@left[8,%fn] but what then?
%@left[8,%fn] but what then?
Best way to validate a string is a YYYYMMDD
- Thread starter Charles G
- Start date
You'll probably want to combine that check with @ISDIGIT, since @ISDATE accepts a lot of other formats.
In the "good old days" we did this without external plugins:
Parse the string to the form YYYY-MM-DD
echo %@makedate[%@date[%string,4],4]
shouldn't produce an error an be identical to the value of %string.
Parse the string to the form YYYY-MM-DD
echo %@makedate[%@date[%string,4],4]
shouldn't produce an error an be identical to the value of %string.
@ISDATE will tell you whether it's a valid date, but not whether it's in the format you want. For example, %@ISDATE[05-23-68] will return 1, even though the date isn't YYYYMMDD. Assuming that you already know the length is 8 characters, you could check for both a valid date and the desired format in one swell foop with something like:
(But note that my idea of a "valid date" includes dates well out of TCC's supported date range.)
Code:
if "%@isdate[%cdate]%@isdigit[%cdate]" == "11" echo Valid date in YYYYMMDD format.(But note that my idea of a "valid date" includes dates well out of TCC's supported date range.)
That second parameter is only used to interpret ambiguous date formats, like 05-11-12. It doesn't enforce any format.
(Klaus's solution is also quite clever; have you checked it out? TCC will happily accept some invalid dates, the 30th of February or whatever. But pushing such an invalid date through @DATE and then @MAKEDATE will give you a valid date back -- which will necessarily be a different string from the one you started with. Elegant!)
