[R] Fwd: as.Date gives NAs when transforming from factor

[PIKAL Petr]

Hi

I did not have problems transforming factors to dates, only when trying to transform nonexistent date.

> as.Date(factor(c("31.3.2015", "29.2.2015")), format="%d.%m.%Y")
[1] "2015-03-31" NA
>
Cheers
Petr

> -----Original Message-----
> From: R-help [mailto:r-help-bounces at r-project.org] On Behalf Of Jeff
> Newmiller
> Sent: Wednesday, April 6, 2016 2:05 AM
> To: Omar André Gonzáles Díaz <oma.gonzales at gmail.com>; r-help at R-
> project.org
> Subject: Re: [R] Fwd: as.Date gives NAs when transforming from factor
>
> Don't give a factor to as.Date. Convert it to character first, or avoid letting it
> become a factor in the first place by using the stringsAsFactors =FALSE option
> to the read.table function or its related functions.
> --
> Sent from my phone. Please excuse my brevity.
>
> On April 5, 2016 4:53:56 PM PDT, "Omar André Gonzáles Díaz"
> <oma.gonzales at gmail.com> wrote:
> >Hi,
> >
> >I would appreciate your help.
> >
> >I’m having problems when transforming  a column from “factor” to
> >“date”.
> >
> >
> >
> >It does not convert just: 31/03/2016 correctly, it out puts: NA.
> >
> >
> >
> >04/04/2016  turns out as: 2016-04-04
> >
> >
> >
> >02/04/2016 turns out as: 2016-02-04
> >
> >
> >
> >31/03/2016 turns out as: NA
> >
> >03/04/2016 turns out as: 2016-03-04.
> >
> >
> >
> >
> >
> >
> >
> >Code:
> >
> >a <- read.csv("dates.csv", stringsAsFactors = F)
> >
> >
> >
> >a$Date <- as.Date(a$Date, format = "%m/%d/%Y")
> >
> >
> >
> >
> >Posible Solutions:
> >
> >
> >
> >I’ve read here that it has to do with the Sys Locale, and the solution
> >was
> >using: “LC_TIME”, “C”. But I didn’t have success.
> >
> >http://stackoverflow.com/questions/15566875/as-date-returning-na-in-r
> >
> >
> >
> >
> >
> >
> ># Sys.getlocale("LC_TIME")
> >
> >#
> >
> ># Sys.setlocale("LC_TIME", "C")
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >Slds,
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
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