lt, <

Determine less than

Description

example

A < B returns an array with elements set to logical 1 (true) where A is less than B; otherwise, the element is logical 0 (false). The test compares only the real part of numeric arrays. lt returns logical 0 (false) where A or B have NaN or undefined categorical elements.

lt(A,B) is an alternate way to execute A < B, but is rarely used. It enables operator overloading for classes.

Examples

collapse all

Determine if vector elements are less than a given value.

Create a numeric vector.

A = [1 12 18 7 9 11 2 15];

Test the vector for elements that are less than 12.

A < 12
ans = 1x8 logical array

   1   0   0   1   1   1   1   0

The result is a vector with values of logical 1 (true) where the elements of A satisfy the expression.

Use the vector of logical values as an index to view the values in A that are less than 12.

A(A < 12)
ans = 1×5

     1     7     9    11     2

The result is a subset of the elements in A.

Create a matrix.

A = magic(4)
A = 4×4

    16     2     3    13
     5    11    10     8
     9     7     6    12
     4    14    15     1

Replace all values less than 9 with the value 10.

A(A < 9) = 10
A = 4×4

    16    10    10    13
    10    11    10    10
     9    10    10    12
    10    14    15    10

The result is a new matrix whose smallest element is 9.

Create an ordinal categorical array.

A = categorical({'large' 'medium' 'small'; 'medium' ...
'small' 'large'},{'small' 'medium' 'large'},'Ordinal',1)
A = 2x3 categorical array
     large       medium      small 
     medium      small       large 

The array has three categories: 'small', 'medium', and 'large'.

Find all values less than the category 'medium'.

A < 'medium'
ans = 2x3 logical array

   0   0   1
   0   1   0

A value of logical 1 (true) indicates a value less than the category 'medium'.

Compare the rows of A.

A(1,:) < A(2,:)
ans = 1x3 logical array

   0   0   1

The function returns logical 1 (true) where the first row has a category value less than the second row.

Create a vector of complex numbers.

A = [1+i 2-2i 1+3i 1-2i 5-i];

Find the values that are less than 3.

A(A < 3)
ans = 1×4 complex

   1.0000 + 1.0000i   2.0000 - 2.0000i   1.0000 + 3.0000i   1.0000 - 2.0000i

lt compares only the real part of the elements in A.

Use abs to find which elements are within a radius of 3 from the origin.

A(abs(A) < 3)
ans = 1×3 complex

   1.0000 + 1.0000i   2.0000 - 2.0000i   1.0000 - 2.0000i

The result has one less element. The element 1.0000 + 3.0000i is not within a radius of 3 from the origin.

Create a vector of dates.

A = datetime([2014,05,01;2014,05,31])
A = 2x1 datetime array
   01-May-2014
   31-May-2014

Find the dates that occur before May 10, 2014.

A(A < '2014-05-10')
ans = datetime
   01-May-2014

Input Arguments

collapse all

Operands, specified as scalars, vectors, matrices, or multidimensional arrays. Numeric or string inputs A and B must either be the same size or have sizes that are compatible (for example, A is an M-by-N matrix and B is a scalar or 1-by-N row vector). For more information, see Compatible Array Sizes for Basic Operations.

You can compare numeric inputs of any type, and the comparison does not suffer loss of precision due to type conversion.

If A and B are categorical, datetime, or duration arrays, then they must be the same size unless one is a scalar.

  • If one input is an ordinal categorical array, the other input can be an ordinal categorical array, a cell array of character vectors, or a single character vector. A single character vector expands into a cell array of character vectors of the same size as the other input. If both inputs are ordinal categorical arrays, they must have the same sets of categories, including their order. See Compare Categorical Array Elements for more details.

  • If one input is a datetime array, the other input can be a datetime array, a character vector, or a cell array of character vectors.

  • If one input is a duration array, the other input can be a duration array or a numeric array. The operator treats each numeric value as a number of standard 24-hour days.

  • If one input is a string array, the other input can be a string array, a character vector, or a cell array of character vectors. The corresponding elements of A and B are compared lexicographically.

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

Compatibility Considerations

expand all

Behavior changed in R2016b

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™.

Introduced before R2006a