[R] Subarrays

Gunnar Hellmund ghellmund at gmail.com
Fri Apr 29 17:33:36 CEST 2005


Define an array

> v<-1:256
> dim(v)<-rep(4,4)

Subarrays can be obtained as follows:

> v[3,2,,2]
[1]  71  87 103 119
> v[3,,,2]
     [,1] [,2] [,3] [,4]
[1,]   67   83   99  115
[2,]   71   87  103  119
[3,]   75   91  107  123
[4,]   79   95  111  127

In the general case this procedure is very tedious. 

Given an array 
A, dim(A)=(dim_1,dim_2,...,dim_d) 
and two vectors
v1=(n_i1,...n_ik), v2=(int_1,...,int_k) ('marginals' and relevant
'interval numbers')
is there a smart way to obtain 
A[,...,int_1,....,int_2,....,....,int_k,....]
?

Best wishes
Gunnar Hellmund




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