datestr producing incorrect dates

Hello everyone,

I am testing some historical data, and and the raw dates import as serialized dates. So when I convert these dates into strings in the 'yyyymmdd' format, I would expect to see the following: 39400 (serial date) converts into 20071114 (November 14, 2007). However, when I use datestr on 39400 I get 01071115. In other words, the year (2007) and the day(14th) are incorrect. Am I missing something? Thanks for reading.

[Azzi Abdelmalek]

Post your code

Answer 1

[per isakson]

"39400" is an "Excel serial date number".

Matlab: A serial date number represents the whole and fractional number of days from a fixed, preset date (January 0, 0000).

See: Represent Dates and Times in MATLAB

Try

    >> datenum( '20071114', 'yyyymmdd' ) 
    ans =
          733360

.

There is a function in the Financial Toolbox, x2mdate, Excel serial date number to MATLAB serial date number. See that documentation and write your own function.

Answer 2

[Cary]

Thank you. How can I prevent the dates from being imported as excel serial numbers (I understand I can use x2mdate if this is not possible)?

[per isakson]

AKAIK: One cannot prevent that and has to convert them in a second step. See my answer.