Is this what you want?
> x <- seq(as.POSIXct("2006-05-05 12:00"), by="17 min", length=20)
> x
[1] "2006-05-05 12:00:00 GMT" "2006-05-05 12:17:00 GMT" "2006-05-05
12:34:00 GMT"
[4] "2006-05-05 12:51:00 GMT" "2006-05-05 13:08:00 GMT" "2006-05-05
13:25:00 GMT"
[7] "2006-05-05 13:42:00 GMT" "2006-0
I have data in Unixtime that I wish to plot several ways. I have
learned to convert to a vector of time strings, and for the sake of
plotting times of day vs. heights of tide (to examine seasonality
component) I can extract HH:mm pretty swiftly and readily from
Unixtime using emacs calc. However,
