Average or mean value of array
M = mean(A) returns the mean value along the first array dimension of A whose size does not equal 1.
If A is a vector, then mean(A) returns the mean of the elements.
If A is a nonempty, nonvector matrix, then mean(A) treats the columns of A as vectors and returns a row vector whose elements are the mean of each column.
If A is an empty 0-by-0 matrix, then mean(A) returns NaN.
If A is a multidimensional array, then mean(A) treats the values along the first array dimension whose size does not equal 1 as vectors and returns an array of row vectors. The size of this dimension becomes 1 while the sizes of all other dimensions remain the same.
Define a 4-by-3 matrix.
A = [0 1 1; 2 3 2; 1 3 2; 4 2 2]
A = 0 1 1 2 3 2 1 3 2 4 2 2
Find the mean value of each column.
M = mean(A)
M = 1.7500 2.2500 1.7500
Define a 2-by-3 matrix.
A = [0 1 1; 2 3 2]
A = 0 1 1 2 3 2
Find the mean value of each row.
M = mean(A,2)
M = 0.6667 2.3333
Create a 1-by-3-by-4 array of integers between 1 and 10.
A = gallery('integerdata',10,[1,3,4],1)
A(:,:,1) = 10 8 10 A(:,:,2) = 6 9 5 A(:,:,3) = 9 6 1 A(:,:,4) = 4 9 5
Find the mean values of this 3-D array along the second dimension.
M = mean(A)
M(:,:,1) = 9.3333 M(:,:,2) = 6.6667 M(:,:,3) = 5.3333 M(:,:,4) = 6
This operation produces a 1-by-1-by-4 array by computing the mean of the three values along the second dimension. The size of the second dimension is reduced to 1.
Compute the mean along the first dimension of A.
M = mean(A,1); isequal(A,M)
ans = 1
This operation returns the same array as A because the size of the first dimension is 1.
Define a 1-by-4 vector of 8-bit integers.
A = int8(1:4)
A = 1 2 3 4
Compute the mean value.
M = mean(A), class(M)
M = 2.5000 ans = double
M is the mean value returned as double. This operation returns the same result as M = mean(A,'default').
Specify type as 'native' to return the mean value as an 8–bit integer.
M = mean(A,'native'), class(M)
M = 3 ans = int8
Input array, specified as a vector, matrix, or multidimensional array.
If A contains NaN or NaT (Not a Time), then M returns NaN or NaT.
Data Types: single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64 | datetime | duration
Dimension to operate along, specified as a positive integer scalar. If no value is specified, the default is the first array dimension whose size does not equal 1.
Dimension dim indicates the dimension whose length reduces to 1. The size(M,dim) is 1, while the sizes of all other dimensions remain the same.
Consider a two-dimensional input array, A.
If dim = 1, then mean(A,1) returns a row vector containing the mean of the elements in each column.
If dim = 2, then mean(A,2) returns a column vector containing the mean of the elements in each row.
mean returns A if dim is greater than ndims(A).
Data Types: double | single | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64
Output class, specified as 'default', 'double', or 'native', and which defines the data type of the output, M.
|type||Output data type|
|'default'||double, unless the input data type is single. In which case, the output data type is single.|
|'native'||same data type as the input array, A|