strange behavior of R

arr

[1] "y1" "y2"

At this moment 'arr' no longer has two dimensions, but only one. So
you can access it only as a vector.

Problem: I want to access the first row now using:

arr[1, ]

Error in arr[1, 1] : incorrect number of dimensions

Correct. It has only one dim.

Though it is showing the value ?as under:

arr[1]

[1] "y1"

arr[2]

[1] "y2"

This is how you would access individual elements in vectors.
Liviu