[Gambas-user] How to verify a date like dd/mm/yyyy?
Benoit Minisini
gambas at ...1...
Fri Mar 21 16:50:57 CET 2008
On vendredi 21 mars 2008, Richard wrote:
> On Friday 21 March 2008 15:11:18 Benoit Minisini wrote:
> > On vendredi 21 mars 2008, Richard wrote:
> > > On Friday 21 March 2008 14:44:51 Richard wrote:
> > > > On Friday 21 March 2008 12:57:04 Richard wrote:
> > > > > On Friday 21 March 2008 07:51:48 andy2 wrote:
> > > > > > in Php i found the following script. My problem is to replicate
> > > > > > the ereg function.
> > > > > >
> > > > > > FUNCTION ControlloData($data){
> > > > > > If(!ereg("^[0-9]{2}/[0-9]{2}/[0-9]{4}$", $data)){
> > > > > > RETURN FALSE;
> > > > > > } ELSE {
> > > > > > $arrayData = explode("/", $data);
> > > > > > $Giorno = $arrayData[0];
> > > > > > $Mese = $arrayData[1];
> > > > > > $Anno = $arrayData[2];
> > > > > > If(!checkdate($Mese, $Giorno, $Anno)){
> > > > > > RETURN FALSE;
> > > > > > } ELSE {
> > > > > > RETURN TRUE;
> > > > > > }
> > > > > > }
> > > > > > }
> > > > > >
> > > > > > -----------------------------------------------------------------
> > > > > >-- -- -- -- This SF.net email is sponsored by: Microsoft
> > > > > > Defy all challenges. Microsoft(R) Visual Studio 2008.
> > > > > > http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/
> > > > > > _______________________________________________
> > > > > > Gambas-user mailing list
> > > > > > Gambas-user at lists.sourceforge.net
> > > > > > https://lists.sourceforge.net/lists/listinfo/gambas-user
> > > > >
> > > > > You could also do something similar to the PHP code:
> > > > >
> > > > > PUBLIC FUNCTION is_date(data AS String) AS Boolean
> > > > > DIM aDateElements AS String[]
> > > > > DIM iDay AS Integer
> > > > > DIM iMth AS Integer
> > > > > DIM iYear AS Integer
> > > > >
> > > > > IF NOT (data LIKE "[0-9][0-9]/[0-9][0-9]/[0-9][0-9][0-9][0-9]")
> > > > > THEN RETURN FALSE
> > > > > ELSE
> > > > > aDateElements = Split(data, "/")
> > > > > iDay = aDateElements[0]
> > > > > iMth = aDateElements[1]
> > > > > iYear = aDateElements[2]
> > > > > TRY RETURN IsDate(Date(iYear, iMth, iDay))
> > > > > IF ERROR THEN RETURN FALSE
> > > > > ENDIF
> > > > >
> > > > > END
> > > > >
> > > > > The Gambas LIKE operator is just as weak as the VB one and the mask
> > > > > I have shown will only check for digits. It will accept digits
> > > > > which do not make up a date (eg 72/33/1234); this is the same
> > > > > behaviour as your PHP regular expression.
> > > > >
> > > > >
> > > > > -------------------------------------------------------------------
> > > > >-- -- -- This SF.net email is sponsored by: Microsoft
> > > > > Defy all challenges. Microsoft(R) Visual Studio 2008.
> > > > > http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/
> > > > > _______________________________________________
> > > > > Gambas-user mailing list
> > > > > Gambas-user at lists.sourceforge.net
> > > > > https://lists.sourceforge.net/lists/listinfo/gambas-user
> > > >
> > > > I suppose, in deference to the peculiar requirements of our northern
> > > > trans-atlantic brethren I should have taken more care in the example
> > > > to make it locale-aware.
> > > >
> > > > The trick, which I found when looking at the ValueBox code, is to
> > > > construct a localised version of the YYYY MM DD format string for a
> > > > gb.ShortDate. When we are extracting day and month from the array of
> > > > date element values we must know which one is the day and which the
> > > > month.
> > > >
> > > > Benoit did it something like this:
> > > >
> > > > sDateFormat = Format(Date(3333, 11, 22), gb.ShortDate)
> > > >
> > > > so now the month is represented by 11 and the day by 22. All we need
> > > > to do is check what the first two digits represent by looking at our
> > > > date format variable before we fetch values from the array.
> > > >
> > > > PUBLIC FUNCTION is_date(data AS String) AS Boolean
> > > > DIM aDateElements AS String[]
> > > > DIM iDay AS Integer
> > > > DIM iMth AS Integer
> > > > DIM iYear AS Integer
> > > > DIM $sDateFormat AS String
> > > >
> > > > sDateFormat = Format(Date(3333, 11, 22), gb.ShortDate)
> > > >
> > > > IF NOT (data LIKE "[0-9][0-9]/[0-9][0-9]/[0-9][0-9][0-9][0-9]")
> > > > THEN RETURN FALSE
> > > > ELSE
> > > > aDateElements = Split(data, "/")
> > > > iDay =
> > > > IIF(LEFT(sDateFormat,2)="22",aDateElements[0],aDateElements[1]) iMth
> > > > = IIF(LEFT(sDateFormat,2)="11",aDateElements[0],aDateElements[1])
> > > > iYear = aDateElements[2]
> > > > TRY RETURN IsDate(Date(iYear, iMth, iDay))
> > > > IF ERROR THEN RETURN FALSE
> > > > ENDIF
> > > >
> > > > END
> > > >
> > > > ---------------------------------------------------------------------
> > > >-- -- This SF.net email is sponsored by: Microsoft
> > > > Defy all challenges. Microsoft(R) Visual Studio 2008.
> > > > http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/
> > > > _______________________________________________
> > > > Gambas-user mailing list
> > > > Gambas-user at lists.sourceforge.net
> > > > https://lists.sourceforge.net/lists/listinfo/gambas-user
> > >
> > > One more attempt to get it right...
> > >
> > > I overlooked the assumption about the date format in the LIKE
> > > expression and the possibility to tighten up the comparison mask to
> > > make it a little more robust (not much).
> > >
> > > PUBLIC FUNCTION is_date(data AS String) AS Boolean
> > > DIM aDateElements AS String[]
> > > DIM iDay AS Integer
> > > DIM iMth AS Integer
> > > DIM iYear AS Integer
> > > DIM sDateFormat AS String
> > > DIM sMask AS String
> > >
> > > sDateFormat = Format(Date(3333, 11, 22), gb.ShortDate)
> > >
> > > IF LEFT(sDateFormat,2)="22" THEN
> > > sMask = "[0-3][0-9]/[0-1][0-9]/[0-9][0-9][0-9][0-9]"
> > > ELSE
> > > sMask = "[0-1][0-9]/[0-3][0-9]/[0-9][0-9][0-9][0-9]"
> > > ENDIF
> > >
> > > IF NOT (data LIKE sMask) THEN
> > > RETURN FALSE
> > > ELSE
> > > aDateElements = Split(data, "/")
> > > iDay =
> > > IIF(LEFT(sDateFormat,2)="22",aDateElements[0],aDateElements[1]) iMth
> > > =IIF(LEFT(sDateFormat,2)="11",aDateElements[0],aDateElements[1]) iYear
> > > = aDateElements[2]
> > > TRY RETURN IsDate(Date(iYear, iMth, iDay))
> > > IF ERROR THEN RETURN FALSE
> > > ENDIF
> > >
> > > END
> > >
> > >
> > > Richard
> >
> > RETURN IsDate(Val(data)) is not complex enough? :-)
>
> You got me there! That gets rid of the possibility of the ERROR on the Date
> conversion, thus removing the need for the TRY.
>
> Presumably it also takes care of localisation so the splitting of the array
> into date elements is redundant, as is the LIKE check against a mask
> string.
>
> My only excuse is that I wanted to make it "look" functionally similar to
> the PHP version, and show off some of Gambas's neat string related features
> (like Split).
>
>
> Richard
> (properly chastened, but not cowed :-)
>
Actually that test returns TRUE when data is a time, not a date, so another
check is needed!
Regards,
--
Benoit Minisini
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