Date: Apr 16, 2013 3:39 PM
Author: dpb
Subject: Re: numel or length, which is better?
On 4/16/2013 2:16 PM, dpb wrote:

> On 4/16/2013 2:03 PM, Hesham Ismail wrote:

...

>> length calculate the number of column whereas numel calculate the number

>> of element

> ...

>

> Not necessarily...

>

...

> As noted in earlier response LENGTH() is max(size(x)) for any x whereas

> NUMEL() is prod(size(x))

>

> If one is interested in rows or columns (and often are) then have to ask

> for the size of the pertinent dimension to be certain....

And to belabor the point but to drive it home...

>> D=rand(2,3,5);

>> length(D)

ans =

5

>> max(size(D))

ans =

5

>> size(D)

ans =

2 3 5

>>

I've used utility functions on occasion for nrows and ncols as syntactic

sugar--they're trivial to write, of course--

function nr=nrows(x)

% N = nrows(A) returns the number of rows, N, in array A.

nr=size(x,1);

function nc=ncols(x)

% N = ncols(A) returns the number of cols, N, in array A.

nc=size(x,2);

--