FreeMat

- Main Page
- Related Pages

NUMEL Number of Elements in an Array

Section: Inspection Functions

# Usage

Returns the number of elements in an array `x`, or in a subindex expression. The syntax for its use is either

       y = numel(x)

or

       y = numel(x,varargin)

Generally, `numel` returns `prod(size(x))`, the number of total elements in `x`. However, you can specify a number of indexing expressions for `varagin` such as `index1, index2, ..., indexm`. In that case, the output of `numel` is `prod(size(x(index1,...,indexm)))`.

# Example

For a `4 x 4 x 3` matrix, the length is `4`, not `48`, as you might expect, but `numel` is `48`.

    --> x = rand(4,4,3);
    --> length(x)

    ans =
     4

    --> numel(x)

    ans =
     48

Here is an example of using `numel` with indexing expressions.

    --> numel(x,1:3,1:2,2)

    ans =
     6