Preserving dates in Excel. - R-help

Thu, Jun 14, 2007 5:49 AM #

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.

Warning message:
class information lost from one or more columns in: data.matrix(head(Banks.Index.daily[, 1:5]))

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

"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


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