How to set ',' as decimal separator with R
Even though my Windows 7 locale settings specify using "," as a decimal separator, R and RStudio give me a "." separator. Is there any way to change this? Note the "LC_NUMERIC=C" setting in the locale below: this seems to be forced by R or RStudio.
As I am in the middle of a long project, I am unwilling to change right away to R 3.0 and the last RStudio version. Does anybody know is there is any change regarding the decimal separator issue in these versions?
I am using prettyNum to solve the problem for single numbers, but I don't know how to use it on a table.
sessionInfo() R version 2.15.3 (2013-03-01) Platform: x86_64-w64-mingw32/x64 (64-bit)
locale:
[1] LC_COLLATE=Spanish_Argentina.1252 LC_CTYPE=Spanish_Argentina.1252
[3] LC_MONETARY=Spanish_Argentina.1252 LC_NUMERIC=C
[5] LC_TIME=Spanish_Argentina.1252
attached base packages:
[1] grid splines stats graphics grDevices utils datasets methods
[9] base
other attached packages:
[1] ascii_2.1 randomForest_4.6-7 pander_0.3.3 fpc_2.1-5
[5] flexmix_2.3-10 mclust_4.0 cluster_1.14.3 MASS_7.3-23
[9] Gmisc_0.5.0.0 testthat_0.7 boot_1.3-7 rms_3.6-3
[13] miscTools_0.6-16 stringr_0.6.2 Hmisc_3.10-1 survival_2.37-2
[17] lattice_0.20-13 xtable_1.7-1 pixmap_0.4-11 RColorBrewer_1.0-5
[21] ade4_1.5-1
loaded via a namespace (and not attached):
[1] digest_0.6.3 evaluate_0.4.3 modeltools_0.2-19 stats4_2.15.3
[5] tools_2.15.3
Answer
The decimal separator used by the read.table and write.table functions (and most of their cousins) is set with "dec" parameter. read.csv2 is a special case where the default for dec is "," and the field separator ("sep") is set to ";".
You can change the output from R printing, plotting and the actions of the as.character function. You change it from its default with:
options(OutDec= ",") # read ?options
print( pi )
#[1] 3,141593
options(OutDec= ",") # restore default value
This will NOT cause R to handle numeric input from the console differently. That is hard-coded to "." as the decimal separator.
If you applied a text function to a table object, you would be possibly coercing from a 'numeric' to a 'character' mode, since table objects in R inherit from the "matrix" class.
It should be added that the "natural" way to read data with "europian" decimal separators is to use read.delim. Not only does it change the decimal separator to "," but at the same time it changes some the parameters to something other than the default for read.table or read.csv:
sep = "\t", quote = "\"", dec = ".", fill = TRUE, comment.char = ""