So by default when a single element of a matrix is retrieved,

is returned to vector of length one, rather than a one by one matrix.

So remember I said that before, the si, the single square operator always

returns an object of the same class, so, the one that's, that sometimes is

a little bit unexpected, is that if I subset out, a single element of a matrix,

I don't get back a matrix, what I get back is just a vector with that number in it,

so if I say x, one, two, that gives the first row second column of the matrix,

that's just a number three, and what I get back is a number three,

[COUGH] not a one by one matrix, with the number three in it.

This is usually what you want, although sometimes it can cause problems, and so

you can turn off this default behavior by adding an extra argument to

the subsetting operation, which is called drop.

And the idea is that by default, drop is equal to true, and

it drops the dimension, and so rather than getting a two dimensional object back,

you, you typically get a one dimensional object back.

However if you want to preserve the dimensions of the object,

you can say drop equal to false and when I subset out the first row,

second column, what I get back is a one by one matrix with the element three in it.