[R] Replace / with - in date

[David Winsemius]

On Apr 15, 2010, at 7:20 PM, prem_R wrote:

>
>> x <- c("2000/01/01",
> "2001
> / 
> 02 
> / 
> 01 
> ","2000 
> / 
> 03 
> / 
> 01 
> ","2000 
> / 
> 04 
> / 
> 01 
> ","2000 
> / 
> 05 
> /01","2000/06/01","2000/07/01","2000/08/01","2000/09/01","2000/10/01")
>> xd <- as.data.frame(x)
>> levels(xd$x) <- gsub("/", "-", levels(xd$x))
>> fix(xd)
>
> This works fine .but with one more variable say xsd in the data  
> frame i'm
> getting the following error
>
>
> Error in levels(sa$date1) <- gsub("/", "-", levels(sa$date)) :
>  attempt to set an attribute on NULL
>

Cannot reproduce the error (and you are asked in the Posting Guide to  
include the code that creates the error rather than posting code that  
does not).

x <- c("2000/01/01",
"2001 
/ 
02 
/ 
01 
","2000 
/ 
03 
/ 
01 
","2000 
/ 
04 
/ 
01 
","2000 
/ 
05/01","2000/06/01","2000/07/01","2000/08/01","2000/09/01","2000/10/01")
xd <- data.frame(x=x, a=1)  # creates another column in "a".
levels(xd$x) <- gsub("/", "-", levels(xd$x))
 > xd
             x a
1  2000-01-01 1
2  2001-02-01 1
3  2000-03-01 1
4  2000-04-01 1
5  2000-05-01 1
6  2000-06-01 1
7  2000-07-01 1
8  2000-08-01 1
9  2000-09-01 1
10 2000-10-01 1

 > sessionInfo()
R version 2.10.1 RC (2009-12-09 r50695)
x86_64-apple-darwin9.8.0

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

attached base packages:
[1] splines   stats     graphics  grDevices utils     datasets   
methods   base

other attached packages:
[1] adapt_1.0-4     Hmisc_3.7-0     survival_2.35-7 mapdata_2.1-1    
maps_2.1-0

loaded via a namespace (and not attached):
[1] cluster_1.12.1 grid_2.10.1    lattice_0.18-3 tools_2.10.1



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David Winsemius, MD
West Hartford, CT