Hi, Is there a function func(x) where x is an array such that it returns a list of the indices of all non-zero elements of the array? for example: a: 1 0 0 0 0 1 0 1 0 func(a) returns two vectors r and c: r c 1 1 2 3 3 2 daver +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |David Richmond It works on a | + Dept. of Sociology complex scientific + |Saint Mary's College principle, known as | + Notre Dame, IN 46556 "pot luck." + |219-284-4517 - The Doctor | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.- r-help mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html Send "info", "help", or "[un]subscribe" (in the "body", not the subject !) To: r-help-request at stat.math.ethz.ch _._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._
find indices of nonzero elements
4 messages · David A Richmond, Jason Turner, Ott Toomet +1 more
Is there a function func(x) where x is an array such that it returns a list of the indices of all non-zero elements of the array?
which() eg.
a<-matrix(c(1,0,0,0,0,1,0,1,0),ncol=3) a
[,1] [,2] [,3] [1,] 1 0 0 [2,] 0 0 1 [3,] 0 1 0
which(a != 0, arr.ind=TRUE)
row col [1,] 1 1 [2,] 3 2 [3,] 2 3 That do? Cheers Jason
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Hi, use: which( a>0, arr.ind=TRUE) best wishes, Ott
On Mon, 8 Oct 2001, David A Richmond wrote:
Hi, Is there a function func(x) where x is an array such that it returns a list of the indices of all non-zero elements of the array? for example: a: 1 0 0 0 0 1 0 1 0 func(a) returns two vectors r and c: r c 1 1 2 3 3 2 daver
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x <- cbind(c(1,0,0),c(0,0,1),c(0,1,0)) x
[,1] [,2] [,3] [1,] 1 0 0 [2,] 0 0 1 [3,] 0 1 0
cbind(row(x)[x!=0],col(x)[x!=0])
[,1] [,2] [1,] 1 1 [2,] 3 2 [3,] 2 3 Agus Dr. Agustin Lobo Instituto de Ciencias de la Tierra (CSIC) Lluis Sole Sabaris s/n 08028 Barcelona SPAIN tel 34 93409 5410 fax 34 93411 0012 alobo at ija.csic.es
On Mon, 8 Oct 2001, David A Richmond wrote:
Hi, Is there a function func(x) where x is an array such that it returns a list of the indices of all non-zero elements of the array? for example: a: 1 0 0 0 0 1 0 1 0 func(a) returns two vectors r and c: r c 1 1 2 3 3 2 daver +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |David Richmond It works on a | + Dept. of Sociology complex scientific + |Saint Mary's College principle, known as | + Notre Dame, IN 46556 "pot luck." + |219-284-4517 - The Doctor | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.- r-help mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html Send "info", "help", or "[un]subscribe" (in the "body", not the subject !) To: r-help-request at stat.math.ethz.ch _._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._
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