converting datetime string to POSIXct date/time format in R

问题

Consider a string in the format

test <- "YYYY-MM-DDT00:00:00.000-08:00"

My goal is to convert those strings to POSIXct format so that I can plot the data. my initial thought was to use

as.POSIXct(test)

...but that seems to truncate the datetime to just date. Any thoughts? The help info for as.POSIXct seems to imply that the input should be date and time separated by a space, not by a "T". Is this my issue?

回答1:

You need to specify a format for your conversion. Take a read of ?strptime to see all of the options for date formats.

#YYYY-MM-DDT00:00:00.000-08:00
test <- "2013-12-25T04:32:16.500-08:00"
z <- as.POSIXct(test,format="%Y-%m-%dT%H:%M:%OS")
op <- options(digits.secs = 3)
z
#[1] "2013-12-25 04:32:16.5 EST"

来源：https://stackoverflow.com/questions/21667212/converting-datetime-string-to-posixct-date-time-format-in-r