Need help understanding arrays

Let's say I have an array A = [1 2 3; 4 5 6]

A =

1 2 3

4 5 6

A(1:2) would simply be

1

4

And A(2:3) would be

4

2

Basically the the 1st and 2nd elements and the 2nd and 3rd elements.

So why then is A(1:2, 2:3)

2 3

5 6

Instead of

1 2

4 5

This is probably a silly question, but I just can't seem to understand this.

Answer 1

[Andrei Bobrov]

for your case:

A ([1:2,2:3])

for:

A(1:2,2:3);% 1:2 - numbers rows, befor the comma
           % 2:3 - numbers columns, after the comma

Answer 2

[Cedric]

It is not a silly question. Your first approach for indexing is called 'linear indexing'; it addresses A as if it were a column vector made of all columns of A appended. Try

 >> A(:)

and you will understand. The second approach is subscript indexing of a block of A made of rows 1 to 2 and columns 2 to 3.