Converting Date formats in R [closed]

Answer 1

To obtain your required format i.e., 2016-month-day , you can use format function once you have converted vector of strings to Date type.

I hope below code snippet clears your doubt.

> d = c("2016-02-08","2016-02-18","2015-02-08","2016-02-02")
> class(d)
[1] "character"
> d = as.Date(d)
> class(d)
[1] "Date"
> d = format(d,"%Y-%b-%d")
> d
[1] "2016-Feb-08" "2016-Feb-18" "2015-Feb-08" "2016-Feb-02"

Format function converts the date type objects into the required format. Refer to this link for more information on date type formatting.

Answer 2

You would use as.Date() to convert between dates saved as character and Date objects.

If you want to change the format of a Date object, you can use format(). You have specified "2016-month-day" as the desired format of the dates in the question, but in the code you provide you are using "%d/%b/%Y". The way this works is: the % indicates that the next character will be a conversion specification, everything else (e.g. (- or /) will be used for finding / adding delimiter to the date representation. (see ?strptime for details).

So in your case, just use

dates <- format(dli$Dates, format = "%Y-%b-%d")

to get the result specified in the text of the question:

[1] "2016-Jan-01" "2016-Jan-02" "2016-Jan-03" "2016-Jan-04" "2016-Jan-05"

or this:

dates <- format(dli$Dates, format = "%Y/%b/%d")

to get what you have used in the code snipped:

[1] "2016/Jan/01" "2016/Jan/02" "2016/Jan/03" "2016/Jan/04" "2016/Jan/05"

Answer 3

You can use the package lubridate to convert to a date with ymd then format it for the way you want it displayed

Dates_df <-  mutate(Dates, dli = format(ymd(dli), "%Y/%b/%d")

(I use dplyr here, I assume you have other variables in Dates)

without dplyr if you just want to keep the dates in a vector:

Dates_vec <-  format(ymd(Dates$dli), "%Y/%b/%d")

Answer 4

If you just want to render your dates in this format, then use format:

x <- as.Date("2016-01-01")
format(x, "%Y %b %a %d")

[1] "2016 Jan Fri 01"

There is a separation of concerns here. If you already have your date information stored in R as date types, then you need not change anything internally to extract further information from those dates.

Demo

Answer 5

Good practice is to store date in R as YYYY-MM-DD, and your strings already seem to be at the good format, but :

The format you're passing to as.Date must describe what the strings contain, not what you're expecting as an output.

"%d/%b/%Y" stands for "day as a number (0-31) slash abbreviated month slash 4-digit year", and your strings format are "4-digit year - month as a number - day as a number".

If you want to format the date, you need to call format :

> date <- "2016-01-01"
> date <- as.Date(date, format = "%Y-%m-%d")
> date
[1] "2016-01-01"
> format(date, "%d/%b/%Y")
[1] "01/jan/2016"