numel

Number of array elements

Description

example

n = numel(A) returns the number of elements, n, in array A, equivalent to prod(size(A)).

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.

n = numel(A)
n = 32

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

A = ["a" "b" "c"; "d" "e" "f"]
A = 2x3 string array
    "a"    "b"    "c"
    "d"    "e"    "f"

n = numel(A)
n = 6

Create a cell array of character vectors.

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

numel counts 4 elements in the array.

n = numel(A)
n = 4

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.

n = numel(A)
n = 20

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, then numel returns the number of characters. However, if A is a string scalar, numel returns 1 because it is a single element of a string array. For example, compare the output of numel for a character vector and string:

    nchar = numel('mytext')
    nchar =
    
         6
    nstr = numel("mytext")
    nstr =
    
         1
    

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