Changing date format to "%d/%m/%Y"
df$ddate <- format(as.Date(df$ddate), "%d/%m/%Y")
df$ddate<-strftime(df$ddate,"%d/%m/%Y")
df$bdate<-strftime(strptime(df$bdate,"%d/%m/%y"),"%d/%m/%Y")
df$wdate<-strftime(strptime(df$wdate,"%d/%m/%y"),"%d/%m/%Y")
Default R
action is to treat strings as factors. Of course, an individual setup may differ from defaults. It's a good practice to change variable values to character
, and then convert it to date
. I often use chron
package - it's nice, simple and what matters the most, it does the job. Only downside of this package lays in time zone handling.
If you don't have chron
installed, do:
install.packages("chron")
# load it
library(chron)
# make dummy data
bdate <- c("09/09/09", "12/05/10", "23/2/09")
wdate <- c("12/10/09", "05/01/07", "19/7/07")
ddate <- c("2009-09-27", "2007-05-18", "2009-09-02")
# notice the last argument, it will not allow creation of factors!
dtf <- data.frame(id = 1:3, bdate, wdate, ddate, stringsAsFactors = FALSE)
# since we have characters, we can do:
foo <- transform(dtf, bdate = chron(bdate, format = "d/m/Y"), wdate = chron(wdate, format = "d/m/Y"), ddate = chron(ddate, format = "y-m-d"))
# check the classes
sapply(foo, class)
# $id
# [1] "integer"
# $bdate
# [1] "dates" "times"
# $wdate
# [1] "dates" "times"
# $ddate
# [1] "dates" "times"
C'est ca... it should do the trick...