[solved] StrToDate - why not?

[Nicole]

Here comes a painful thing. Painful, because it takes about 15 minutes of processing until I see this error message

[Content]
"29/04/1983" is not a valid date format.

Press OK to ignore and risk data corruption.
Press Abort to kill the program.

[OK] [Abort]

Can anybody give me a hint, why this date format is not valid?

[wp]

What are your FormatSettings?

This works for me, in Germany where FormatSettings.DateSeparator = '.' (and it should work everywhere):

Code: Pascal  [Select][+][-]

1. program Project1;
2.  
3. uses
4.   SysUtils;
5. var
6.   s: String;
7.   d: TDate;
8. begin
9.   s := '29/04/1983';
10.   FormatSettings.ShortDateFormat := 'dd/mm/yyyy';
11.   FormatSettings.DateSeparator := '/';   // remove this line and you'll have the error when the default DateSeparor is not a '/'
12.   d := StrToDate(s);
13.   WriteLn(s, ' --> ' , DateToStr(d));
14.  
15.   ReadLn;
16.  
17. end.

[Nicole]

I just wrote
myDate:=StrToDate(s);   

The format is a thing, I can configure.
I thought Delphi would understand dd/mm/yyyy

All formats are possible.

[winni]

Hi!

"29/04/1983" is british

"29.04.1983" is german

"04/29/1983" is US

"1983-04-29" is ISO

tbc ...

Winni

[wp]

I thought Delphi would understand dd/mm/yyyy

It's the same as with Lazarus - I just checked it.

It depends on what is listed in the FormatSettings. "dd/mm/yyyy" defines mainly one thing: the order of day-month-year elements (and the number of digits to be used for day/month/year, but this is ignored in the conversion from string to date). The other important thing is the date separator. When the format string is parsed, the '/' is replaced by the date separator. In Germany, the date separator is '.', therefore Lazarus (as well as Delphi) expects a '.' between day and month and between month and year - but you give it a slash. This will fail in all countries in which the date sepator is not a slash.

Only when you specify the date separator to be a '.' it will work.

[Nicole]

Thank you all for the answers.
Indeed: The software, which is the source of the text-generation, - it is from the USA.

I was glad, that I could bring it to  dd / mm / yyyy instead from mm / dd / yyyy, which I never can get used to.
So I will check, if I can change the separator or even better, try to define it, which looks more robust.

[Thaddy]

The programmer's way of handling dates is year first, month second, day third and then time. And all in UTC.
@Nicole : That is the native representation in - almost - all programming languages. What you see on screen is a formatting representation depending on natural language and should never be how it is stored. Homework: How does TDateTime work?. Should be comprehensible in under 10 minutes. Representation should be handled through TFormatSettings.

[Nicole]

FormatSettings.DateSeparator := '/';
solves it.

It is a format, which contains just the date.

[Thaddy]

We almost all know, but I am afraid you still not know date and time handling in programming.