Parse datetime with lubridate

问题

I am trying to parse the following datetime with the following format:

library(lubridate)
a <- "2004-05-07 18:24:58.666424"

I tried the following, but returned NAs

b <- lubridate::mdy_hms(a)
c <- lubridate::mdy(a)

Could anyone please explain how to parse this. I am also fine if lubridate is not used.

回答1:

With lubridate, you can specify that your seconds have a decimal with the special S! or OS formats; see ?parse_date_time for more parsing options.

> parse_date_time("2004-05-07 18:24:58.666424", 'ymd HMS!')
[1] "2004-05-07 18:24:58 UTC"

Alternately, it seems to parse fine with just the usual default "ymd HMS":

parse_date_time("2004-05-07 18:24:58.666424", 'ymd HMS')

or the shorthand

ymd_hms("2004-05-07 18:24:58.666424")

回答2:

Try

options(digits.secs=6)
as.POSIXct(a,"%Y-%m-%d %H:%M:%S.%OS")
#[1] "2004-05-07 18:24:58.666424"

回答3:

mdy=Month day year, your data is setup as ymd

Try ymd_hms or ymd

来源：https://stackoverflow.com/questions/35807501/parse-datetime-with-lubridate