Read in dates with as.Date from character %d%b%Y

Question

This works:

as.Date("22JAN2010", format="%d%b%Y")
>"2010-01-22"

This doesn't:

as.Date("22MAR2010", format="%d%b%Y")
>NA

It breaks on MAR, MAY, OCT and works for JAN, FEB, APR, JUN, JUL, AUG, SEP, NOV, DEC.

Coincidentally, my Windows 7 OS language is in Dutch, for which the date abbreviations would be MAA, MEI, OKT. But those don't work either.

change your locale with `Sys.setlocale(LC_TIME = 'en_GB.UTF-8')` — Jaap, Feb 24 '17 at 16:11
`as.Date("22MAR2010", format="%d%b%Y", tz="UTC")` Gave an NA as well. `> Sys.setlocale(LC_TIME = 'en_GB.UTF-8') Error in Sys.setlocale(LC_TIME = "en_GB.UTF-8") : unused argument (LC_TIME = "en_GB.UTF-8")` — DaReal, Feb 24 '17 at 16:13
http://stackoverflow.com/questions/15566875/as-date-returning-na-while-converting-from-ddmmmyyyy — CClaire, Feb 24 '17 at 16:14
@CClaire, that's the one, thanks! Didn't pop up in SO search for me. — DaReal, Feb 24 '17 at 16:17
Sorry, correct one should be: `Sys.setlocale('LC_TIME','en_GB.UTF-8')` — Jaap, Feb 24 '17 at 16:24

IRTFM · Answer 1 · 2017-02-24T16:36:19.330

You can find out what monthly abbreviations are going to be recognized with the in-built data object: month.abb which is internationalized.

 month.abb
 [1] "Jan" "Feb" "Mar" "Apr" "May" "Jun" "Jul" "Aug" "Sep" "Oct" "Nov" "Dec"

The sessionInfo() function also returns the locale, which for me is:

locale:
[1] en_US.UTF-8/en_US.UTF-8/en_US.UTF-8/C/en_US.UTF-8/en_US.UTF-8

... and could have gotten that single vector with Sys.getlocale() but I suspect you have something else set. As commented by @Jaap, the value is under your control with Sys.setlocale. The particular value of the 'LC_TIME' item should be used by strptime which is at the core of the as.Dat.character function.

(The Sys.setlocale function has 2 named arguments "category" and "locale" which is why the first suggestion to use Sys.setlocale(LC_TIME = "en_GB.UTF-8") failed. It seemed to be typical R syntax to my eyes as well, since the usual pairlist formalism doesn't quote the names. I've made that mistake many times.)

Read in dates with as.Date from character %d%b%Y

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