help with gsub and date pattern
Here are a few more to add to the list.
x <- c("5/31/2009 12:34:00","6/1/2009 1:14:00")
# 1
read.table(textConnection(x), as.is = TRUE)[, 2]
# 2
format(as.POSIXct(x, format = "%m/%d/%Y %H:%M:%S"), "%H:%M:%S")
# 3
library(gsubfn)
strapply(x, "[0-9]*:..:..", simplify = c)
Also see R News 4/1.
On Thu, May 21, 2009 at 5:34 PM, Marc Schwartz <marc_schwartz at me.com> wrote:
On May 21, 2009, at 4:13 PM, Tim Clark wrote:
Dear List,
I am having a problem using gsub to remove dates from a date/time string.
For example:
x<-c("5/31/2009 12:34:00","6/1/2009 1:14:00")
I would like to remove the date and have just the time.
I have tried:
gsub("[0-9+]/[0-9+]/[0-9+]","",x)
and various versions. ?I think my problem is that the / is a special
character and is telling it something that I don't mean. ?I would appreciate
any suggestions on how to proceed.
Thanks,
Tim
Switch the '+' to outside the brackets:
gsub("[0-9]+/[0-9]+/[0-9]+ ","",x)
[1] "12:34:00" "1:14:00" A few other options: # Use strsplit
sapply(strsplit(x, split = " "), "[", 2)
[1] "12:34:00" "1:14:00" # Return the pattern contained within the parens # See ?regex
gsub("^.* (.*)$", "\\1", x)
[1] "12:34:00" "1:14:00" # Replace the characters up to the space with an empty vector
gsub("^.* ", "", x)
[1] "12:34:00" "1:14:00" HTH, Marc Schwartz