In R, how to convert a string like “Saturday, 5 Oct 2013 20:31:59” to “2013-10-05 Saturday 20:31:59”?

Question

How to convert a string which is Saturday, 5 Oct 2013 20:31:59 to a datetime format 2013-10-05 Saturday 20:31:59 ? Thanks. Or how to get the year , month , date , day of the week , hour , minute , second values from the string?

Answer 1

You need to use the relevant format specification when you create the time object from the string, eg:

(x <- as.POSIXct("Saturday, 5 Oct 2013 20:31:59", format="%A, %d %b %Y %H:%M:%S"))
[1] "2013-10-05 20:31:59 BST"

Look at ?strftime to see the format specifications, and how to extract specific parts of a datetime.

#your desired format
format(x, "%Y-%m-%d %A %H:%M:%S")
[1] "2013-10-05 Saturday 20:31:59"
#only the year
format(x,"%Y")
[1] "2013"

Answer 2

> now <- Sys.time()
> now
[1] "2014-01-16 16:58:23 IST"
> as.POSIXlt(as.character(now),tz="GMT")
[1] "2014-01-16 17:05:24 GMT"
> str(as.POSIXlt(now))
 POSIXlt[1:1], format: "2014-01-16 16:58:23"
> unclass(as.POSIXlt(now))
$sec
[1] 23.1636

$min
[1] 58

$hour
[1] 16

$mday
[1] 16

$mon
[1] 0

$year
[1] 114

$wday
[1] 4

$yday
[1] 15

$isdst
[1] 0

Answer 3

Using the lubridate package.

library(lubridate)
x <- "Saturday, 5 Oct 2013 20:31:59"
dmy_hms(x)
## [1] "2013-10-05 20:31:59 UTC"

Answer 4

library(lubridate)

R> date <- now()

R> year(date)

use the below accessor for other

Date component Accessor
Year           year()
Month          month()
Week           week()
Day of year    yday()
Day of month   mday()
Day of week    wday()
Hour           hour()
Minute         minute()
Second         second()
Time           zone tz()