MATLAB^®

any - Determine whether any array elements are nonzero

Syntax

B = any(A) B = any(A,dim)

Description

B = any(A) tests whether any of the elements along various dimensions of an array is a nonzero number or is logical 1 (true). any ignores entries that are NaN (Not a Number).

If A is a vector, any(A) returns logical 1 (true) if any of the elements of A is a nonzero number or is logical 1 (true), and returns logical 0 (false) if all the elements are zero.

If A is a matrix, any(A) treats the columns of A as vectors, returning a row vector of logical 1's and 0's.

If A is a multidimensional array, any(A) treats the values along the first nonsingleton dimension as vectors, returning a logical condition for each vector.

B = any(A,dim) tests along the dimension of A specified by scalar dim.

Examples

Example 1 – Reducing a Logical Vector to a Scalar Condition

Given

A = [0.53 0.67 0.01 0.38 0.07 0.42 0.69]

then B = (A < 0.5) returns logical 1 (true) only where A is less than one half:

0   0   1   1   1   1   0

The any function reduces such a vector of logical conditions to a single condition. In this case, any(B) yields logical 1.

This makes any particularly useful in if statements:

if any(A < 0.5)do something
end

where code is executed depending on a single condition, not a vector of possibly conflicting conditions.

Example 2– Reducing a Logical Matrix to a Scalar Condition

Applying the any function twice to a matrix, as in any(any(A)), always reduces it to a scalar condition.

any(any(eye(3)))
ans =
   1

Example 3 – Testing Arrays of Any Dimension

You can use the following type of statement on an array of any dimensions. This example tests a 3-D array to see if any of its elements are greater than 3:

x = rand(3,7,5) * 5;

any(x(:) > 3)
ans =
     1

or less than zero:

any(x(:) < 0)
ans =
     0