mustBeGreaterThan

Validate that value is greater than another value

Syntax

mustBeGreaterThan(value,c)

Description

mustBeGreaterThan(value,c) throws an error if any elements in value are less than or equal to c. This function does not return a value.

mustBeGreaterThan calls the gt function to determine if value is greater than c. (since R2026a)

Class support: All numeric classes, logical, and MATLAB^® classes that implement gt.

This function ignores empty values in the first input argument. Therefore, no error is thrown when the property or function argument value is empty.

Examples

Validate First Input Greater Than Second

Use mustBeGreaterThan to validate that the values in the first input are greater than the value of the second input.

mustBeGreaterThan([2 3 4],2)

Value must be greater than 2.

Restrict Property Values

This class restricts the value of Prop1 to be greater than 2.

classdef MyClass
   properties
      Prop1 {mustBeGreaterThan(Prop1,2)}
   end
end

Create an object and assign a value to its property.

obj = MyClass;
obj.Prop1 = 2;

Error setting property 'Prop1' of class 'MyClass'. Value must be greater than 2.

When you assign a value to the property, MATLAB calls mustBeGreaterThan with the value being assigned to the property. mustBeGreaterThan issues an error because the value 2 is not greater than 2.

Restrict Function Argument Values

This function restricts the input argument to be values that are greater than 5.

function r = mbGreaterThan(x)
    arguments
        x {mustBeGreaterThan(x,5)}
    end
    r = x - 5;
end

Calling the function with a vector that contains values that are less than or equal to 5 does not meet the requirements defined with mustBeGreaterThan and results in an error.

x = [12.7, 45.4, 5.0, 77.1, 53.1];
r = mbGreaterThan(x);

Error using mbGreaterThan (line 3)
 r = mbGreaterThan(x);
                   ^
Invalid argument at position 1. Value must be greater than 5.

Input Arguments

value — Value to validate

scalar | array

Value to validate, specified as a scalar or an array of one of these types:

• logical, char, string, or numeric class

• MATLAB classes that implement gt

Data Types: single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64 | logical | char | string | categorical | datetime | duration | table | timetable
Complex Number Support: Yes

c — Constant value that the value argument must be greater than

scalar | array

Constant value that the value argument must be greater than, specified as a scalar or an array of one of these types:

• logical, char, string, or numeric class

• MATLAB classes that implement gt

Inputs c and value must have compatible sizes (for example, value is an M-by-N matrix and c is a scalar or 1-by-N row vector). For more information, see Compatible Array Sizes for Basic Operations.

Before R2026a: c must be scalar.

Data Types: single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64 | logical | char | string | categorical | datetime | duration | table | timetable
Complex Number Support: Yes

Tips

• mustBeGreaterThan is designed to be used for property and function argument validation.

Extended Capabilities

C/C++ Code Generation
Generate C and C++ code using MATLAB® Coder™.

GPU Code Generation
Generate CUDA® code for NVIDIA® GPUs using GPU Coder™.

GPU Arrays

Accelerate code by running on a graphics processing unit (GPU) using Parallel Computing Toolbox™.

The mustBeGreaterThan 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).

Distributed Arrays

Partition large arrays across the combined memory of your cluster using Parallel Computing Toolbox™.

The mustBeGreaterThan function fully supports distributed arrays. For more information, see Run MATLAB Functions with Distributed Arrays (Parallel Computing Toolbox).

Version History

Introduced in R2017a

R2026a: mustBeGreaterThan no longer restricts inputs to be real, numeric, or logical

The mustBeGreaterThan function no longer calls the isreal, isnumeric, and islogical functions to validate input. As a result, mustBeGreaterThan accepts any data type supported by the underlying comparison operator gt (or >), such as character vectors, strings, and date and time types.

For example, the compareValues function restricts input argument values using the mustBeGreaterThan validation function.

function obj = compareValues(startValue,endValue)
    arguments
        startValue
        endValue {mustBeGreaterThan(endValue,startValue)}
    end
end

The compareValues function now accepts data of type datetime as input.

A = datetime("yesterday");
B = datetime("today");
compareValues(A,B)

In previous releases, calling compareValues with datetime inputs returned this error:

Error using compareValues (line 4)
Inputs to function 'mustBeGreaterThan' must be numeric or logical.

To preserve the behavior of previous releases, explicitly use mustBeReal and mustBeNumericOrLogical in your validation checks. For example, this code preserves the previous behavior of mustBeGreaterThan in the compareValues function definition.

function obj = compareValues(startValue,endValue)
    arguments
        startValue {mustBeReal,mustBeNumericOrLogical}
        endValue {mustBeReal,mustBeNumericOrLogical, ...
                  mustBeGreaterThan(endValue,startValue)}
    end
end

R2026a: Compare two inputs with compatible array sizes

The mustBeGreaterThan function now supports implicit expansion when comparing two inputs with compatible array sizes, similar to the implicit expansion behavior in arithmetic operations.

For example, the compareValues function restricts input argument values using the mustBeGreaterThan validation function.

function obj = compareValues(startValue,endValue)
    arguments
        startValue
        endValue {mustBeGreaterThan(endValue,startValue)}
    end
end

The compareValues function now accepts inputs with compatible array sizes.

compareValues([-2; -1],[3 2 1])

In previous releases, calling compareValues on 2-by-1 and 1-by-3 input arrays returned this error:

Error using compareValues (line 4)
Second input to function 'mustBeGreaterThan' must be a scalar.