向量转换为列表的问题

Question

I have read in two data matrices using read.table, and wish to find the intersection between the header list of M1 and a vector in M2. However, if I use intersect(names(M1),M2[2,]), I get an error message because M2[2,] is a vector while M1 is a list. I thought that using as.list(M2[2,]) would correct this problem, but it does not. How can I convert the data structure of vector M2[2,] into a list so that its intersection with names(M1) would be a defined operation?

Answer 1

(This is too long for a comment.)

The following works for me:

set.seed(3)

M1 = data.frame(matrix(runif(100), ncol=5))
colnames(M1) = letters[1:5]

M2 = data.frame(matrix(rnorm(100), nrow=5))
M2[2,] = sample(letters, 20, replace=T)
intersect(names(M1),M2[2,])

Can you say more about your situation, and what is not working? It may help to read this: how-to-make-a-great-r-reproducible-example .