[R] matching matrix columns to a vector

Salas, Andria Kay aks2515 at uncw.edu
Mon Nov 24 17:03:45 CET 2008

I need help with (hopefully) just one more thing.  I have been fussing with this for quite some time and have decided just to give up and ask!  I want to match a column in a matrix to a vector.  I found a "which" command that I thought would be helpful as it does the following:

> g=c(1,5,3,2,7)
> which(g==5)
[1] 2

As the above gave which placement in the g vector corresponded to 5 (the second place), I need this command to give me which column in a matrix matches to a vector.

This is just a toy example of what I am trying to do:
> t=matrix(1:12,3,4)

This does not work, and with my "real" matrices and vectors, I was getting outputs that did not make sense.  These examples are more to give an idea of what I am aiming to accomplish.

Thank you for all the help!!

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