[R] vector of NA indices

[Ben Bolker]

On Wed, 14 Jul 1999, Peter B. Mandeville wrote:

> I have a vector Pes with 600 elements some of which are NA's. How can I
> form a vector of the indices of the NA's.
> 
> 	for(i in 1:600) if(is.na(Pes[i])) print(i)
> 
> prints the indices of the NA's but I can't figure out how to put the
> results in a vector.
> 
> Thank you very much.
> 
> Peter B.

x <- 1:100
> x[round(runif(20)*100)] <- NA
> (1:length(x))[is.na(x)]
 [1]  1  2  3 17 23 24 31 54 58 64 70 76 84 85 92 96


 (or in your case,

(1:600)[is.na(Pes)]

 )

Benjamin Bolker          Dep't of Ecology and Evolutionary Biology,
ben at eno.princeton.edu    Princeton University
tel: (609) 258-6886,     fax: (609) 258-1334

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