On 23/06/2017 15:35, Joris Meys wrote:
Related to the following question on Stackoverflow:
https://stackoverflow.com/questions/44723690/unexpected-behavior-of-sys-setlocale#44723690
It appears as if Sys.setlocale() does not update LC_TIME correctly for use
in date formatting. Although R reports that LC_TIME is changed to the new
setting after use of Sys.setlocale(), as.Date() still uses the old
settings. The only way to update this is by specifically using LC_TIME.
Is this a bug or am I overlooking something?
Try setting the LC_TIME category explicitly. The mapping of day/month
names used by strptime (not really as.Date, and not taken from LC_TIME)
is then reset.
Since Windows does not have a usable strptime C function, a substitute
is used and its handing of non-English names is not done through the
OS's locale mechanism.
Example:
Sys.setlocale(locale = "French_Belgium")
[1]
"LC_COLLATE=French_Belgium.1252;LC_CTYPE=French_Belgium.1252;LC_MONETARY=French_Belgium.1252;LC_NUMERIC=C;LC_TIME=French_Belgium.1252"
date <- "Dec-11"
as.Date(date, format = "%b-%d")
[1] NA # expected
Sys.setlocale(locale = "English_United Kingdom")
[1] "LC_COLLATE=English_United Kingdom.1252;LC_CTYPE=English_United
Kingdom.1252;LC_MONETARY=English_United
Kingdom.1252;LC_NUMERIC=C;LC_TIME=English_United Kingdom.1252"
as.Date(date, format = "%b-%d")
[1] NA # not expected, should be a correct date
Sys.setlocale("LC_TIME", "English_United Kingdom")
[1] "English_United Kingdom.1252"
as.Date(date, format = "%b-%d")
[1] "2017-12-11" # expected
Sys.setlocale(locale = "French_Belgium")
[1]
"LC_COLLATE=French_Belgium.1252;LC_CTYPE=French_Belgium.1252;LC_MONETARY=French_Belgium.1252;LC_NUMERIC=C;LC_TIME=French_Belgium.1252"
as.Date(date, format = "%b-%d")
[1] "2017-12-11" # not expected, should be NA
Sys.setlocale("LC_TIME", "French_Belgium")
[1] "French_Belgium.1252"
as.Date(date, format = "%b-%d")
[1] NA # expected
sessionInfo()
R version 3.4.0 (2017-04-21)
Platform: x86_64-w64-mingw32/x64 (64-bit)
Running under: Windows 7 x64 (build 7601) Service Pack 1
Matrix products: default
locale:
[1] LC_COLLATE=French_Belgium.1252 LC_CTYPE=French_Belgium.1252
[3] LC_MONETARY=French_Belgium.1252 LC_NUMERIC=C
[5] LC_TIME=French_Belgium.1252
attached base packages:
[1] stats graphics grDevices utils datasets methods base
other attached packages:
[1] shiny_1.0.3
loaded via a namespace (and not attached):
[1] compiler_3.4.0 R6_2.2.1 htmltools_0.3.6 tools_3.4.0
Rcpp_0.12.10
[6] digest_0.6.12 xtable_1.8-2 httpuv_1.3.3 mime_0.5
--
Brian D. Ripley, rip...@stats.ox.ac.uk
Emeritus Professor of Applied Statistics, University of Oxford
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