isempty - Determine whether array is empty - MATLAB (original) (raw)

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Determine whether array is empty

Syntax

Description

TF = isempty([A](#d126e921195)) returns logical 1 (true) if A is empty, and logical 0 (false) otherwise. An empty array, table, or timetable has at least one dimension with length 0, such as 0-by-0 or 0-by-5.

example

Examples

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Create a 3-D array with one dimension length equal to zero, and determine if it is empty.

A = zeros(0,2,2); TF = isempty(A)

Compare empty arrays to arrays containing missing values.

In MATLAB®, an empty array has at least one dimension length equal to zero. An array containing missing values, such as NaN or <undefined>, is not necessarily empty.

Create a categorical vector with missing values.

cat1 = categorical([missing missing])

cat1 = 1×2 categorical

Since cat1 does not have a dimension of length zero, it is not empty.

Create a 0-by-0 categorical array and test if it is empty.

cat2 = categorical([]); TF2 = isempty(cat2)

Compare empty string arrays and strings with no characters.

Create a string vector whose elements are strings with no characters. str1 is nonempty since none of its dimensions have length zero.

str1 = 1×3 string "" "" ""

Create a 0-by-3 string array and test if it is empty.

str2 = strings(0,3); TF2 = isempty(str2)

Input Arguments

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

Tips

• To determine whether a string array has empty strings (string elements with zero characters), use the == operator. For example, ifstr is a string containing zero characters, then str == "" returns logical 1 (true). For more information on testing empty strings, see Test for Empty Strings and Missing Values. For information on string comparison, see Compare Text.
• To test for missing values in an array, use the ismissing function.

Extended Capabilities

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

The isempty 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