Finding the column with the maximum value by row

Hi,
Try,
apply(a,1,which.max)
[1] 3 1 3

A.K.



----- Original Message -----
From: Christopher Desjardins <cddesjardins at gmail.com>
To: r-help at r-project.org
Cc: 
Sent: Tuesday, July 17, 2012 6:03 PM
Subject: [R] Finding the column with the maximum value by row

Hi,
Let's say I have the following data:

a=matrix(c(1,2,4,4,2,1,1,2,4),nrow=3,byrow=T)

a

? ?  [,1] [,2] [,3]

[1,]? ? 1? ? 2? ? 4

[2,]? ? 4? ? 2? ? 1

[3,]? ? 1? ? 2? ? 4

What syntax should I use to get R to tell me the column that corresponds to
the maximum value for each row?

For my example, I would like to get a vector that says 3, 1, 3 because the
maximum value for row 1 is in column 3, the maximum value for row 2 is in
column 1, and the maximum value for row 3 is in column 3.

Does that make sense?

Please cc me if you reply!

Chris

??? [[alternative HTML version deleted]]

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