Finding pattern in a matrix in R

Question

I have a 8 x n matrix, for instance

set.seed(12345)
m <- matrix(sample(1:50, 800, replace=T), ncol=8)
head(m)

     [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8         


        

Answer 1

Here's one way using sapply:

which(sapply(seq(nrow(m)-2),
             function(x)
               isTRUE(37 %in% m[x,] & 
                      which(10 == m[x+1,]) < which(29 == m[x+1,]) & 
                      42 %in% m[x+2,])))

The result contains all row number where the sequence starts:

[1] 57