Converts numbers like 42370
into date values like
2016-01-01
.
Defaults to the modern Excel date encoding system. However, Excel for Mac
2008 and earlier Mac versions of Excel used a different date system. To
determine what platform to specify: if the date 2016-01-01 is represented by
the number 42370 in your spreadsheet, it's the modern system. If it's 40908,
it's the old Mac system. More on date encoding systems at
http://support.office.com/en-us/article/Date-calculations-in-Excel-e7fe7167-48a9-4b96-bb53-5612a800b487.
A list of all timezones is available from base::OlsonNames()
, and the
current timezone is available from base::Sys.timezone()
.
If your input data has a mix of Excel numeric dates and actual dates, see the
more powerful functions convert_to_date()
and convert_to_datetime()
.