Message-ID: <1BDAE2969943D540934EE8B4EF68F95FB22F48CE94@EXNSW-MBX03.nexus.csiro.au>
Date: 2009-04-05T23:02:37Z
From: Bill Venables
Subject: number of zeros in a matrix -row by row
In-Reply-To: <22893147.post@talk.nabble.com>
> M <- matrix(0:15, 8, 4, byrow=TRUE)
> rowSums(M == 0)
[1] 1 0 0 0 1 0 0 0
Bill Venables
http://www.cmis.csiro.au/bill.venables/
-----Original Message-----
From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org] On Behalf Of onyourmark
Sent: Sunday, 5 April 2009 10:00 PM
To: r-help at r-project.org
Subject: [R] number of zeros in a matrix -row by row
Hi. I have an n x m matrix M some of who's entries are zeros. I want to know
how many zeros there are in each row -perhaps stored in a 1 x n vector
which lists the number of zeros for each row of M.
Before I had a vector V and I was able to get the number of zeros in V by
doing length(V[ V==0]) but when I try something similar for M, like M[ M==0]
it creates a vector not a matrix and so this does not work. Does anyone have
a solution to this?
Thank you.
--
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