R help - Apr 2010 - question about fold function

Dear all,

I'm trying to use the fold function as described here:
http://cran.r-project.org/doc/contrib/Fox-Companion/appendix-cox-regression.pdf 
Page9

It does say that you can use this when you have more than one time varying 
covariate: in the description of the argument cov it says:
"cov: A vector giving the column numbers of the time-dependent covariate in
data, or a list of vectors
if there is more than one time-dependent covariate."

But I'm struggling with the syntax to list these vectors (I have 2 time
varying
covariates). But this just gives me an error message. 
>d6#my data 
  SURVIVAL DEAD STARTYEAR SMALLINNO TOTALINNO ADVERTISE  WAGE PRICECOST CAPITAL
ENTRYRATE   CR4
1        1    0      1999     1.724     1.724    0.3580 6.154    22.422   5.480 
22.92 42.24
2        1    0      1999     1.942     1.942    0.2262 8.197    24.161  12.534 
24.75 28.29
3        1    0      1999     1.942     1.942    0.2262 8.197    24.161  12.534 
24.75 28.29
    MSE OWNER PROV STARTSIZE NEWPROD1 NEWPROD2 NEWPROD3 NEWPROD4 NEWPROD5
NEWPROD6 NEWPROD7
1 46236     1   42    0.8769        0       NA       NA       NA       NA      
NA       NA
2 93340     1   42    0.1926        0       NA       NA       NA       NA      
NA       NA
3 93340     1   43    0.0000        0       NA       NA       NA       NA      
NA       NA
  NEWPROD8 RD1 RD2 RD3 RD4 RD5 RD6 RD7 RD8
1       NA   0  NA  NA  NA  NA  NA  NA  NA
2       NA   0  NA  NA  NA  NA  NA  NA  NA
3       NA   0  NA  NA  NA  NA  NA  NA  NA
>
d4<-fold(d6,time='survival',event='dead',cov=c(16:23,24:31),cov.names=c('newproduct','R&D'))
Error in dimnames(x) <-dn:
    length of 'dimnames' [2] not equal to array extent

Would you mind give me some advice?

Thanks in advance


2010-04-07 



Mingqian

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