I have a very large Excel file with dates in the format 2013/01/17 08:02:00 PM which is a custom date format. I have to convert this file to CSV in order to import it into Mathematica because I can't get around the Java heap space error (I have tried the suggestions on this site).
When I convert it to CSV the dates automatically change to the number format eg 40969.00069 which I think represents the number of days since 1900. This is a standard date format that is sometimes used in Excel and automatically used when I save the Excel file as a CSV.
When I now import the CSV file into Mathematica the dates stay in this number format. How can I get Mathematica to understand these 'number formatted dates'? When I tried the following code, just trying to get a year from the number formatted date, Mathematica returned 1900 no matter what year in number format I apply it to. This tells me that Mathematica doesn't understand what these numbers are.
I have looked at the help files and searched on this site but I can't seem to solve this.