Re: [Rd] matrix operations

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

Melanie Vida <mvida <at> mac.com> 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:

See
?order
?sort

m[order(m[,1]),] # sorts so that column 1 is sorted and rows stay together apply(m, 2, sort) # sort each column separately



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https://stat.ethz.ch/mailman/listinfo/r-devel Received on Mon Feb 21 02:26:23 2005

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