false - Logical 0 (false) - MATLAB (original) (raw)

Syntax

Description

false is shorthand for the logical value 0.

[F](#bt7y3qf-F) = false([n](#bt7y3qf-n)) is an n-by-n array of logical zeros.

[F](#bt7y3qf-F) = false([sz](#bt7y3qf-sz)) is an array of logical zeros where the size vector, sz, defines size(F). For example, false([2 3]) returns a 2-by-3 array of logical zeros.

example

[F](#bt7y3qf-F) = false([sz1,...,szN](#bt7y3qf-sz1szN)) is a sz1-by-...-by-szN array of logical zeros where sz1,...,szN indicates the size of each dimension. For example, false(2,3) returns a 2-by-3 array of logical zeros.

example

[F](#bt7y3qf-F) = false(___,like=[p](#bt7y3qf-p)) returns an array of logical zeros of the same sparsity as the logical variablep using any of the previous size syntaxes.

example

Examples

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Use false to generate a 3-by-3 square matrix of logical zeros.

A = 3×3 logical array

0 0 0 0 0 0 0 0 0

The result is of class logical.

Use false to generate a 3-by-2-by-2 array of logical zeros.

ans = 3×2×2 logical array ans(:,:,1) =

0 0 0 0 0 0

ans(:,:,2) =

0 0 0 0 0 0

Alternatively, use a size vector to specify the size of the matrix.

ans = 3×2×2 logical array ans(:,:,1) =

0 0 0 0 0 0

ans(:,:,2) =

0 0 0 0 0 0

Note that specifying multiple vector inputs returns an error.

false along with true can be used to execute logic statements.

Test the logical statement

~(A and B) = (~A) or (~B)

for A = false and B = true.

~~(false & true) == (~~false) | (~true)

The result is logical 1 (true), since the logical statements on both sides of the equation are equivalent. This logical statement is an instance of De Morgan's Law.

Generate a logical array of the same data type and sparsity as the selected array.

A = logical(sparse(5,3)); whos A

Name Size Bytes Class Attributes

A 5x3 41 logical sparse

F = false(4,like=A); whos F

Name Size Bytes Class Attributes

F 4x4 49 logical sparse

The output array F has the same sparse attribute as the specified array A.

Input Arguments

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Size of square matrix, specified as an integer. n sets the output array size to n-by-n. For example, false(3) returns a 3-by-3 array of logical zeros.

If n is 0, then F is an empty matrix.
If n is negative, then it is treated as 0.

Size vector, specified as a row vector of integers. For example, false([2 3)] returns a 2-by-3 array of logical zeros.

If the size of any dimension is 0, then F is an empty array.
If the size of any dimension is negative, then it is treated as 0.
If any trailing dimensions greater than 2 have a size of 1, then the output, F, does not include those dimensions.

Size inputs, specified by a comma-separated list of integers. For example, false(2,3) returns a 2-by-3 array of logical zeros.

If the size of any dimension is 0, then F is an empty array.
If the size of any dimension is negative, then it is treated as 0.
If any trailing dimensions greater than 2 have a size of 1, then the output, F, does not include those dimensions.

Prototype, specified as a logical variable.

Output Arguments

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Output of logical zeros, returned as a scalar, vector, matrix, or N-D array.

Data Types: logical

Tips

false(n) is much faster and more memory efficient than logical(zeros(n)).

Extended Capabilities

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Usage notes and limitations:

Dimensions must be real, nonnegative, integers.

The false 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