[R] Preserving dates in Excel.

[Patnaik, Tirthankar]

Hi Peter, Prof. Ripley,

	You're right--I just realized I was exporting a matrix, after converting the data-frame using data.matrix, where the date characteristics are lost.

 
Basically a function I was running converted the dataframe to a matrix first--something I'd forgotten.

> z1 <- data.matrix(head(Banks.Index.daily[,1:5]))
Warning message:
class information lost from one or more columns in: data.matrix(head(Banks.Index.daily[, 1:5])) 
> z1
            Date   SBI.BO HDFC.BO KTKM.BO YESB.BO
2001-01-01 11323 102944.3 64134.8  3576.4      NA
2001-01-02 11324 108812.5 64390.9  3606.2      NA
2001-01-03 11325 114101.8 65909.5  3528.2      NA
2001-01-04 11326 112180.8 65266.3  3691.2      NA
2001-01-05 11327 113365.0 69286.3  3700.3      NA
2001-01-08 11330 112180.8 70292.8  3682.0      NA
> write.table(z1)
"Date" "SBI.BO" "HDFC.BO" "KTKM.BO" "YESB.BO"
"2001-01-01" 11323 102944.3 64134.8 3576.4 NA
"2001-01-02" 11324 108812.5 64390.9 3606.2 NA
"2001-01-03" 11325 114101.8 65909.5 3528.2 NA
"2001-01-04" 11326 112180.8 65266.3 3691.2 NA
"2001-01-05" 11327 113365 69286.3 3700.3 NA
"2001-01-08" 11330 112180.8 70292.8 3682 NA
> 

Apologies for the inconvenience.

Best,
-Tir


> -----Original Message-----
> From: Peter Dalgaard [mailto:P.Dalgaard at biostat.ku.dk] 
> Sent: Thursday, June 14, 2007 6:07 PM
> To: Patnaik, Tirthankar [GWM-CIR]
> Cc: r-help at stat.math.ethz.ch
> Subject: Re: [R] Preserving dates in Excel.
> 
> Patnaik, Tirthankar wrote:
> > Hi,
> > 	Quick question: Say I have a date variable in a data 
> frame or matrix, 
> > and I'd like to preserve the date format when using write.table.
> > However, when I export the data, I get the generic number 
> underlying 
> > the date, not the date per se, and a number such as 11323, 
> 11324, etc 
> > are not meaningful in Excel. Is there any way I can preserve the 
> > format of a date on writing into a text-file?
> >
> >   
> Er, what is exactly the problem here?
> 
> > d <- data.frame(date=as.Date("2007-6-1")+1:5, x=rnorm(5)) d
>         date             x
> 1 2007-06-02  0.7987635130
> 2 2007-06-03 -0.7381623316
> 3 2007-06-04 -1.3626708691
> 4 2007-06-05  0.0007668082
> 5 2007-06-06  0.6719088533
> > write.table(d)
> "date" "x"
> "1" 2007-06-02 0.798763513018864
> "2" 2007-06-03 -0.738162331606612
> "3" 2007-06-04 -1.36267086906438
> "4" 2007-06-05 0.000766808196322155
> "5" 2007-06-06 0.671908853312511
> > write.csv(d)
> "","date","x"
> "1",2007-06-02,0.798763513018864
> "2",2007-06-03,-0.738162331606612
> "3",2007-06-04,-1.36267086906438
> "4",2007-06-05,0.000766808196322155
> "5",2007-06-06,0.671908853312511
> 
> 
> -- 
>    O__  ---- Peter Dalgaard             Øster Farimagsgade 5, Entr.B
>   c/ /'_ --- Dept. of Biostatistics     PO Box 2099, 1014 Cph. K
>  (*) \(*) -- University of Copenhagen   Denmark          Ph:  
> (+45) 35327918
> ~~~~~~~~~~ - (p.dalgaard at biostat.ku.dk)                  FAX: 
> (+45) 35327907
> 
> 
>