Reputation: 1120
How to tell R to cbind two matrix only if they have the same number of rows ?
I know that I can check it manually.
Upvotes: 0
Views: 89
Reputation: 94202
Make a function, like:
ckbind = function (a, b)
{
a = as.matrix(a)
b = as.matrix(b)
if (nrow(a) == nrow(b)) {
return(cbind(a, b))
} else {
stop("Differing number of rows")
}
}
Note the matrix conversion so it works with vectors. Test:
> ckbind(1:3,2:4)
[,1] [,2]
[1,] 1 2
[2,] 2 3
[3,] 3 4
> ckbind(1:3,2:6)
Error in ckbind(1:3, 2:6) : Differing number of rows
and check it works with matrices:
> ckbind( ckbind(1:3,2:4), ckbind(3:5,4:6))
[,1] [,2] [,3] [,4]
[1,] 1 2 3 4
[2,] 2 3 4 5
[3,] 3 4 5 6
Upvotes: 3