An embedded and charset-unspecified text was scrubbed... Name: not available URL: <https://stat.ethz.ch/pipermail/r-help/attachments/20131101/3a74d1c2/attachment.pl>
find max value in each row and return column number and column name
4 messages · Gary Dong, Clint Bowman, arun +1 more
?which.max should start you down the right path
Clint Bowman INTERNET: clint at ecy.wa.gov
Air Quality Modeler INTERNET: clint at math.utah.edu
Department of Ecology VOICE: (360) 407-6815
PO Box 47600 FAX: (360) 407-7534
Olympia, WA 98504-7600
USPS: PO Box 47600, Olympia, WA 98504-7600
Parcels: 300 Desmond Drive, Lacey, WA 98503-1274
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
[[alternative HTML version deleted]]
______________________________________________ R-help at r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
Hi,
Try:
? cbind(a,do.call(rbind,apply(a,1,function(x) {data.frame(max=max(x), max.col.num=which.max(x), max.col.name=names(a)[which.max(x)],stringsAsFactors=FALSE)}))) ##assuming that unique max for each row.
A.K.
On Friday, November 1, 2013 1:05 PM, Gary Dong <pdxgary163 at gmail.com> 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 ??? [[alternative HTML version deleted]] ______________________________________________ R-help at r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
On Nov 1, 2013, at 10:03 AM, 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!
cbind(a, max=apply(a,1,max),
max.col.num =apply(a,1,which.max) ,
max.col.name= names(a)[apply(a,1,which.max)] )
Thank you! Gary [[alternative HTML version deleted]]
You can express your appreciation by posting in plain-text in the future.
______________________________________________ R-help at r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
David Winsemius Alameda, CA, USA