Cell Array referencing question

Hello,

Suppose I have

A = {1 2}

A = 

      [1]    [2]

and

B = {[1 2]}

B = 

      [1x2 double]

I am wondering, why are these different. Matlab Says A is a 1x1 cell, and B is a 1x2 cell. I am confused about what matlab is doing when it sees this and why it is being classified as such.

[the cyclist]

You might learn from this introduction to cell arrays.

Answer 1

[the cyclist]

Your first statement is syntactically equivalent to

A = {[1],[2]};

This is specifying that A is a 1x2 cell array, where the first element is the length-1 vector [1], and the second element is [2].

In your second statement,

B = {[1 2]}

you have specified that B is a 1x1 cell array, where the contents of that one cell is the 1x2 vector [1 2].

Does that help?

[Rick]

How is matlab reading this?

B = {3,4}; C = [{3},{4}];

They are equivalent. B has two cells in one cell array. C is two cell arrays each containing one cell. Why are they the same?

[the cyclist]

In your first example, B is the direct specification of a 1x2 cell array.

In your second example, {3} is a 1x1 cell array, {4} is a 1x1 cell array, and then C is the concatenation of those "horizontally", creating a 1x2 cell array.

Hence, the equivalence.

Answer 2

[Ben11]

Actually B contains a 1x2 double and it contains only 1 element (a 1x2 vector) whereas A contains 2 elements, i.e. 2 1x1 vectors if you wish