[R] tapply question

[Uwe Ligges]

Frank Johannes wrote:

> HI,
> Suppose I have the following data structure.
>            LRT  tp
> 1   1.50654010 522
> 2   0.51793929 522
> 3   0.90340299 522
> 4   1.20293325 522
> 5   1.05578774 523
> 6   0.01617942 523
> 7   0.68183543 523
> 8   0.43820244 523
> 9   1.14123995 524
> 10  0.05809550 524
> 11  0.93061597 524
> 12  1.39739700 524
> 13  1.05220953 525
> 14  0.03471461 525
> 15  0.63168798 525
> 16  1.40592603 525
> 17  1.41884492 526
> 18  0.23388479 526
> 19  0.21881064 526
> 20  0.99710830 526
> 21  2.02054187 527
> 22  1.99872887 527
> 23  1.04187450 527
> 24  1.31556807 527
> 25  2.77775190 528
> 26  2.94778561 528
> 27  1.88800177 528
> 28  2.08249941 528
> 
> 
> I have succesfully used a command line such as the one below to get
> maxima for each "tp-category'
> 
> data.out<-data[tapply(LRT,tp, function(x) which(LRT==max(x))),]
> 
> However, when I try it on the above data, it gives me the following
> error message:
> 
>>Error in "[.data.frame"(data, tapply(LRT, tp, function(x) which(LRT ==  : 
> 
>         invalid subscript type


Works for me. Look at your data structures and check whether your data 
frame is OK.

Or much better easier:

   tapply(LRT, tp, max)

Uwe Ligges




> I don't know what to do.
> Thanks for your help
> 
> --
> 
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