Thank you Arun!

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-----Original Message-----
From: "arun kirshna [via R]" <ml-node+s789695n4685806h49@n4.nabble.com>
Date: Tue, 25 Feb 2014 10:54:10 
To: bex<elisabetta.petracci@gmail.com>
Subject: Re: how to extract consecutive subvetors of different lengths from
 an existing vector and create a matrix



Hi,

One way would be:

res <- t(sapply(split(y,rep(seq_along(n),n)),function(x) {if(length(x) < max(n)) c(x,rep(NA,max(n)-length(x))) else x}))
A.K.


Dear all, 

my question regards how to subset an existing vector in 
subvectors of different lengths and then create a matrix. See example 
below. 

I have vectors: 

y<-c(1,1,1,0,0,1,1) 
n<-c(3,2,2) 

and I'd like to create the matrix A of the following form: 

1 1  1 
0 0 NA 
1 1 NA 

I'd like to "cut" y sequentially based on information in vector 
n, that is, generating 3 subvectors (the first with the first 3 elements
 of y, the second with the other 2 elements of y, and the last one with 
the latter 2 elements of y) and creating a matrix A (with dimensions, 
no.of rows=length(n), no. of col=max(n) and including NAs where 
necessary. 

Hope to have been clear. 

Bex

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