Re: [Rd] matrix operations

From: Gabor Grothendieck <>
Date: Mon 21 Feb 2005 - 03:16:15 EST

Melanie Vida <mvida <at>> writes:

: In R, I'm imported a data frame of 2,321,123 by 4 called "dataF".
: I converted the data frame "dataF" to a matrix
: dataM <- as.matrix(dataF)
: Does R have an efficient routine to treat the special elements that
: contain "inf" in them. For example, can you separate the rows that have
: "inf" elements from the matrix into a separate matrix without iterating
: over the entire matrix?

This will eliminate all rows that contain Inf or -Inf.

m[apply(is.finite(m), 1, all),]

: Also, does R have an efficient way to sort columns in a matrix?

This can be interpreted a number of different ways:


m[order(m[,1]),] # sorts so that column 1 is sorted and rows stay together apply(m, 2, sort) # sort each column separately mailing list Received on Mon Feb 21 02:26:23 2005

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