Find all rows of matrix equal to vector

Question

Suppose I have the following matrix:

cm<-structure(c(100, 200, 400, 800, 100, 200, 400, 800, 100, 200, 
400, 800, 100, 200, 400, 800, 100, 200, 400, 800,          


        

Answer 1

The function row.match in prodlim is easy to use, and ideal for your problem.

library(prodlim)
row.match(a4[1,], cm[,1:3])
[1] 1