numel - Number of array elements - MATLAB (original) (raw)

Syntax

Description

n = numel([A](#btl24wx-1-A)) returns the number of elements, n, in array A, equivalent to prod(size(A)).

example

Examples

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Create a 4-by-4-by-2 matrix.

A = magic(4); A(:,:,2) = A'

A = A(:,:,1) =

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

A(:,:,2) =

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

numel counts 32 elements in the matrix.

Create a string array and compute the number of elements in the array.

A = ["a" "b" "c"; "d" "e" "f"]

A = 2×3 string "a" "b" "c" "d" "e" "f"

Create a cell array of character vectors.

A = {'dog','cat','fish','horse'};

numel counts 4 elements in the array.

Create a table with four variables listing patient information for five people.

LastName = {'Smith';'Johnson';'Williams';'Jones';'Brown'}; Age = [38;43;38;40;49]; Height = [71;69;64;67;64]; Weight = [176;163;131;133;119]; BloodPressure = [124 93; 109 77; 125 83; 117 75; 122 80];

A = table(Age,Height,Weight,BloodPressure,'RowNames',LastName)

A=5×4 table Age Height Weight BloodPressure ___ ______ ______ _____________

Smith       38       71       176       124     93  
Johnson     43       69       163       109     77  
Williams    38       64       131       125     83  
Jones       40       67       133       117     75  
Brown       49       64       119       122     80

Find the number of elements in the table.

numel returns a value equivalent to prod(size(A)) corresponding to the 5 rows and 4 variables.

Input Arguments

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

Tips

If A is a table, numel returns the number of elements in the table, A, equivalent to prod(size(A)). Variables in a table can have multiple columns, but numel(A) only accounts for the number of rows and number of variables.
If A is a character vector of type char, thennumel returns the number of characters. However, ifA is a string scalar, numel returns1 because it is a single element of a string array. For example, compare the output of numel for a character vector and string:

Extended Capabilities

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

The numel 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