Reading a date

[TonioIncredible]

Good morning,
I am reading an Excel sheet which contains dates. When I open the file with Excel, I see dates, but when I import the file with PHPSpreadSheet, sometimes I get a date (like "23/03/1970") or sometimes I get a number representing a date (like "25940" instead of "07/01/1971").

How can I systematically get a date?

Thanks for your answer
Antoine

[MarkBaker]

I can see that I'm going to have to rewrite the documentation to be very explicit about how dates work in MS Excel; and explain how to read dates as well as write them. This article explains in more detail about dates in MS Excel.

TLDR: MS Excel maintains dates as a serialized timestamp, a numeric value that represents the number of days since a base start date of 1/1/1900 (or 1/1/1904 if the file was created using the Apple Mac version of Microsoft Office). This is similar to a unix timestamp, a numeric value representing a date.

If you get a value of "23/03/1970", then you're getting a string; just because it looks like a date to a human, it's still a string. if you're getting a value of 25940, that could be a date, or simply a number. The only difference between a date and a number is the number format mask.

If you know that a cell should contain a date, then the Cell's getFormattedValue() method should return that value as a human-readable formatted string, similar to "07/01/1971" (although the exact formatting will depend on the formatting mask).

The PhpOffice\PhpSpreadsheet\Shared\Date class provides a series of methods to convert between Excel timestamps and unix timestamp, PHP DateTime object, and formatted strings (and vice versa).

PhpSpreadsheet also provides a method to determine if a cell value is a number or a date

PhpOffice\PhpSpreadsheet\Shared\Date::isDateTime($worksheet->getCell('A1'));

[TonioIncredible]

Thanks,
I will try that.