Hello, I have a data set matrix of 1200 * 15. How can I get the position of a specific value in the matrix? I use "seq(along = x)[x > value]" to look for the position of the value in the matrix, but "seq" can just find the sequence position row by row in the matrix, not a real position (like "rowNumber, colNumber"). Is any function for that? Thank you, Shengzhe
Use which(..., arr.ind=TRUE); e.g.,> m <- matrix(runif(12), 3, 4) > which(m > .8, arr.ind=TRUE)row col [1,] 1 3 [2,] 2 3 [3,] 3 3 [4,] 3 4> m[,1] [,2] [,3] [,4] [1,] 0.2148183 0.08251853 0.9444718 0.4487148 [2,] 0.5386863 0.49673282 0.8054240 0.5101593 [3,] 0.6252847 0.70974516 0.8858951 0.8590655 Andy> From: wu sz > > Hello, > > I have a data set matrix of 1200 * 15. How can I get the position of a > specific value in the matrix? > > I use "seq(along = x)[x > value]" to look for the position of the > value in the matrix, but "seq" can just find the sequence position row > by row in the matrix, not a real position (like "rowNumber, > colNumber"). Is any function for that? > > Thank you, > Shengzhe > > ______________________________________________ > R-help at stat.math.ethz.ch mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide! > http://www.R-project.org/posting-guide.html > > >
Simon Blomberg
2005-Jul-13 23:41 UTC
[R] help: how to get the position of a value in a matrix
See ?which Hint: arr.ind=TRUE Simon. At 09:28 AM 14/07/2005, wu sz wrote:>Hello, > >I have a data set matrix of 1200 * 15. How can I get the position of a >specific value in the matrix? > >I use "seq(along = x)[x > value]" to look for the position of the >value in the matrix, but "seq" can just find the sequence position row >by row in the matrix, not a real position (like "rowNumber, >colNumber"). Is any function for that? > >Thank you, >Shengzhe > >______________________________________________ >R-help at stat.math.ethz.ch mailing list >https://stat.ethz.ch/mailman/listinfo/r-help >PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html