[R] dates in French format

[Prof Brian Ripley]

The output from sessionInfo() the posting guide asked for would have been 
very helpful here.

I think the problem is likely to be that these are not standard French
abbreviations according to my systems.  On Linux I get

> format(Sys.Date(), "%d-%b-%y")
[1] "31-jan-08"
> format(Sys.Date()-50, "%d-%b-%y")
[1] "12-déc-07"

and on Windows

> format(Sys.Date(), "%d-%b-%y")
[1] "31-janv.-08"

> format(Sys.Date()-50, "%d-%b-%y")
[1] "12-déc.-07"

And yes, chron is US-centric and so only allows English names.

Assuming you know exactly what is meant by 'French short format', I think 
the simplest thing to do is to set up a table by

tr <- month.abb
names(tr)[1] <- c("janv")  # complete it

x <- "9-janv-08"
x2 <- strsplit(x, "-")
x3 <- sapply(x2, function(x) {x[2] <- tr[x[2]]; paste(x, collapse="-")})
as.Date(x3, format = "%d-%b-%y")


On Wed, 30 Jan 2008, Denis Chabot wrote:

> Hello R users,
>
> I have to import a file with one column containing dates written in
> French short format, such as:
>
>    7-déc-07
>   11-déc-07
>   14-déc-07
>   18-déc-07
>   21-déc-07
>   24-déc-07
>   26-déc-07
>   28-déc-07
>   31-déc-07
>   2-janv-08
>   4-janv-08
>   7-janv-08
>   9-janv-08
>  11-janv-08
>  14-janv-08
>  16-janv-08
>  18-janv-08
>
> There are other columns for other (numeric) variables in the data
> file. In my read.csv2 statement, I indicate that the date column must
> be imported "as.is" to keep it as character.
>
> I would like to transform this into a date object in R. So far I've
> used chron for my dates and times needs, but I am willing to change if
> another object/package will ease the task of importing these dates.
>
> My reading of the chron help led me to believe that the formats it
> understands are only month names in English.
>
> Are there other "formats" I can use with chron, or must I somehow edit
> this character variables to replace French month names by English ones
> (or numbers from 1 to 12)?
>
> Thanks in advance,
>
> Denis
> p.s. I read this in digest mode, so I'll get your replies faster if
> you cc to my email
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>

-- 
Brian D. Ripley,                  ripley at stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
1 South Parks Road,                     +44 1865 272866 (PA)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595