isnan - Determine which array elements are NaN - MATLAB (original) (raw)

Determine which array elements are NaN

Syntax

Description

`TF` = isnan([A](#mw%5Fdb2dcfa9-acb4-48e9-a017-ee0c39f1f741)) returns a logical array containing 1 (true) where the elements of A are NaN, and 0 (false) where they are not. If A contains complex numbers, isnan(A) contains 1 for elements with either real or imaginary part is NaN, and 0 for elements where both real and imaginary parts are not NaN.

example

Examples

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Create a row vector and determine which elements are NaN.

TF = 1×5 logical array

0 0 1 0 0

Create an array of complex numbers. Determine whether the complex numbers contain NaN.

A = [2 + 1i, 1/0 + 3i, 1/2 - 1i*NaN]

A = 1×3 complex

2.0000 + 1.0000i Inf + 3.0000i 0.5000 + NaNi

TF = 1×3 logical array

0 0 1

Create an array and find the elements with NaN values.

A = [1,3,5,7,NaN,10,NaN,4,6,8]

A = 1×10

 1     3     5     7   NaN    10   NaN     4     6     8

TF = 1×10 logical array

0 0 0 0 1 0 1 0 0 0

Index into A with TF to access the elements of A that are NaN. Replace the NaN values with 0.

A = 1×10

 1     3     5     7     0    10     0     4     6     8

Input Arguments

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Input array, specified as a scalar, vector, matrix, or multidimensional array.

Tips

• If x is a real scalar, exactly one ofisfinite(x), isinf(x), andisnan(x) returns logical 1 (true).
• For a complex scalar z, isinf(z) andisnan(z) can both return logical 1. For example,isinf(complex(Inf,NaN)) andisnan(complex(Inf,NaN)) both return logical 1.

Extended Capabilities

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Theisnan function fully supports tall arrays. For more information, see Tall Arrays.

The isnan function fully supports GPU arrays. To run the function on a GPU, specify the input data as a gpuArray (Parallel Computing Toolbox). For more information, see Run MATLAB Functions on a GPU (Parallel Computing Toolbox).

Version History

Introduced before R2006a