How to take a part of matrix, which is function result?

My code is like this.

A = [1 2; 3 4];
B = sum(A) % I want to use fft or other functions rather than 'sum'
x = B(1)

Then, the result is

B = 4 6

x = 4

If I want to take part of the function directly, that is like

x = sum(A)(1)

How can I do it?

Answer 1

[Walter Roberson]

Nth = @(M, varargin) M(varargin{:});

After which you can

x = Nth(sum(A), 1);

There is no syntax for indexing the result of a function: there is only a way to use an auxillary function to express the indexing in expression form instead of having to always assign to a temporary variable and index that variable.

[Junho Kweon]

OMG, that's such an easy way! Thanks pal :)