[R] as.Date error

[David Winsemius]

On Apr 17, 2011, at 7:24 PM, Wonjae Lee wrote:

>
> Thank you for replying the as.Date error question.
>
> I have one more question as below.
> I used cbind command, and data x changed, 2010-11-16 to 14929,  
> 2010-11-17 to
> 14930.
> What happened to them?
> What should I do to see yyyy-mm-dd format data?
>
>> x=c("11/16/2010","11/17/2010","11/18/2010","11/19/2010")
>> x=as.Date(x,"%m/%d/%Y")
>> x
> [1] "2010-11-16" "2010-11-17" "2010-11-18" "2010-11-19"
>> y=c(1753.75,15077,1759.35,15078)
>> cbind(x,y)
>         x        y
> [1,] 14929  1753.75
> [2,] 14930 15077.00
> [3,] 14931  1759.35
> [4,] 14932 15078.00
>

cbind.default will return a matrix which needs to have all of its  
elements of the same type, so your dates were coerced to numeric since  
their internal representation is as integers.

Had you created x as a data.frame, then cbind would have called  
cbind.data.frame which was probably what you wanted to happen.

 > xdat <-data.frame(x=as.Date(x,"%m/%d/%Y"))
 > cbind(xdat,y)
            x        y
1 2010-11-16  1753.75
2 2010-11-17 15077.00
3 2010-11-18  1759.35
4 2010-11-19 15078.00

-- 

David Winsemius, MD
West Hartford, CT