Separating date and time

[Van Ha]

Hi All: I'm having difficulty separating the date and time from each other. I tried yearly(), date (), and year(dofm()) with no success. Any clue how I get just the year as its own variable?

* Example generated by -dataex-. For more info, type help dataex
clear
input double ct_datetime_num
1.8099198e+12
1.8009297e+12
1800772320000
1.7995776e+12
1798796940000
end
format %tc ct_datetime_num

[Clyde Schechter]

gen int date = dofc(ct_datetime_num)
format date %td
gen int year = year(date)

Or, if you don't actually need the whole date, just the year, you can do it in one line as:

gen int year = year(dofc(ct_datetime_num))

Added: by the way, yearly(), date (), and year(dofm()) are functional expressions that calculate a numeric year from a string variable containg only a year, a Stata internal format numeric daily date variable from a string containing a human-readable date, and the year extracted from a Stata internal format monthly date variable, respectively.

[Van Ha]

Thank you Clyde!