Datenum incoherent documentation

>> datenum('13/03/2011',24)
ans =
        6819
>> datenum('12/03/2011',24)
ans =
      734840

datenum('13/03/2011','dd/mm/yyyy') % correct!!

Vista32 R2011a

Answer 1

[Jan]

Welcome in the team: http://www.mathworks.com/matlabcentral/newsreader/view_thread/285808

[Oleg Komarov]

Thanks, this answers completely my question.

Answer 2

[Walter Roberson]

That is the format for specifying a pivot year to datenum. Pivot years are only used when the year is decoded as two digits -- which happens in this case because 13 is recognized as not being a valid month number. You can see that the first field is being interpreted as a month number by default by using datestr(734840) which returns 03-Dec-2011

[Oleg Komarov]

http://www.mathworks.com/help/techdoc/ref/datenum.html

Expected behaviour:

DateNumber = datenum(DateString, FieldSpecIn)

But then, for bacward compatibility:

DateNumber = datenum(DateString, PivotYear)

Which one should predominate?

[Walter Roberson]

The documentation of the two argument format says "format string FieldSpecIn" implying a string must be used. The three-argument format says "format FieldSpecIn" which does not inherently restrict to strings.

The documentation could use improvement ;-(

[Oleg Komarov]

Arrrrrr...