Strange behavior with as.character

Question

I have a vector or POSIXct and when I do as.character() on it, it returns numbers instead of the characters. I unfortunately cannot reproduce this with toy data but this is what is happening:

d = as.POSIXct(c( "2015-09-08 17:42:07.456 GMT","2015-09-08 17:42:19.778 GMT"))
class(d) ##this returns POSIXct

but as.character(d) returns

"1441740168.0001", "1441740168.0001"

Why am I getting "1441740168.0001", "1441740168.0001" instead of dates in character format?

Answer 1

Internally it represents dates as seconds passed since origin moment in time. Consult this for details.