find max value in each row and return column number and column name
?which.max should start you down the right path
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On Fri, 1 Nov 2013, Gary Dong wrote:
Dear R users, I wonder how I can use R to identify the max value of each row, the column number column name: For example: a <- data.frame(x = rnorm(4), y = rnorm(4), z = rnorm(4))
a
x y z
1 -0.7289964 0.2194702 -2.4674780
2 1.0889353 0.3167629 -0.9208548
3 -0.6374692 -1.7249049 0.6567313
4 -0.1348642 0.4507473 -1.7309010
In this data frame, I compare y and z only.
What I need:
x y z
max max.col.num max.col.name
1 -0.7289964 0.2194702 -2.4674780 0.2194702 2
y
2 1.0889353 0.3167629 -0.9208548 0.3167629 2
y
3 -0.6374692 -1.7249049 0.6567313 0.6567313 3
z
4 -0.1348642 0.4507473 -1.7309010 0.4507473 2
y
Any suggestion will be greatly appreciated!
Thank you!
Gary
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