# mean

Average or mean value of array

## Syntax

``M = mean(A)``
``M = mean(A,"all")``
``M = mean(A,dim)``
``M = mean(A,vecdim)``
``M = mean(___,outtype)``
``M = mean(___,missingflag)``

## Description

example

````M = mean(A)` returns the mean of the elements of `A` along the first array dimension whose size is greater than 1.If `A` is a vector, then `mean(A)` returns the mean of the elements.If `A` is a matrix, then `mean(A)` returns a row vector containing the mean of each column.If `A` is a multidimensional array, then `mean(A)` operates along the first array dimension whose size is greater than 1, treating the elements as vectors. The size of `M` in this dimension becomes `1`, while the sizes of all other dimensions remain the same as in `A`.If `A` is a table or timetable, then `mean(A)` returns a one-row table containing the mean of each variable. (since R2023a)```

example

````M = mean(A,"all")` returns the mean over all elements of `A`.```

example

````M = mean(A,dim)` returns the mean along dimension `dim`. For example, if `A` is a matrix, then `mean(A,2)` returns a column vector containing the mean of each row.```

example

````M = mean(A,vecdim)` returns the mean based on the dimensions specified in the vector `vecdim`. For example, if `A` is a matrix, then `mean(A,[1 2])` returns the mean of all elements in `A` because every element of a matrix is contained in the array slice defined by dimensions 1 and 2.```

example

````M = mean(___,outtype)` returns the mean with a specified data type for any of the previous syntaxes. `outtype` can be `"default"`, `"double"`, or `"native"`.```

example

````M = mean(___,missingflag)` specifies whether to include or omit missing values in `A`. For example, `mean(A,"omitmissing")` ignores all missing values when computing the mean. By default, `mean` includes missing values.```

## Examples

collapse all

Create a matrix and compute the mean of each column.

`A = [0 1 1; 2 3 2; 1 3 2; 4 2 2]`
```A = 4×3 0 1 1 2 3 2 1 3 2 4 2 2 ```
`M = mean(A)`
```M = 1×3 1.7500 2.2500 1.7500 ```

Create a matrix and compute the mean of each row.

`A = [0 1 1; 2 3 2; 3 0 1; 1 2 3]`
```A = 4×3 0 1 1 2 3 2 3 0 1 1 2 3 ```
`M = mean(A,2)`
```M = 4×1 0.6667 2.3333 1.3333 2.0000 ```

Create a 4-by-2-by-3 array of integers between 1 and 10 and compute the mean values along the second dimension.

```rng('default') A = randi(10,[4,2,3]); M = mean(A,2)```
```M = M(:,:,1) = 8.0000 5.5000 2.5000 8.0000 M(:,:,2) = 10.0000 7.5000 5.5000 6.0000 M(:,:,3) = 6.0000 5.5000 8.5000 10.0000 ```

Create a 3-D array and compute the mean over each page of data (rows and columns).

```A(:,:,1) = [2 4; -2 1]; A(:,:,2) = [9 13; -5 7]; A(:,:,3) = [4 4; 8 -3]; M1 = mean(A,[1 2])```
```M1 = M1(:,:,1) = 1.2500 M1(:,:,2) = 6 M1(:,:,3) = 3.2500 ```

To compute the mean over all dimensions of an array, you can either specify each dimension in the vector dimension argument, or use the `"all"` option.

`M2 = mean(A,[1 2 3])`
```M2 = 3.5000 ```
`Mall = mean(A,"all")`
```Mall = 3.5000 ```

Create a single-precision vector of ones and compute its single-precision mean.

```A = single(ones(10,1)); M = mean(A,"native")```
```M = single 1 ```

The result is also in single precision.

`class(M)`
```ans = 'single' ```

Create a matrix containing `NaN` values.

`A = [1.77 -0.005 NaN -2.95; NaN 0.34 NaN 0.19]`
```A = 2×4 1.7700 -0.0050 NaN -2.9500 NaN 0.3400 NaN 0.1900 ```

Compute the mean values of the matrix, excluding missing values. For matrix columns that contain any `NaN` value, `mean` computes with the non-`NaN` elements. For matrix columns that contain all `NaN` values, the mean is `NaN`.

`M = mean(A,"omitnan")`
```M = 1×4 1.7700 0.1675 NaN -1.3800 ```

## Input Arguments

collapse all

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

• If `A` is a scalar, then `mean(A)` returns `A`.

• If `A` is an empty 0-by-0 matrix, then `mean(A)` returns `NaN`.

Data Types: `single` | `double` | `int8` | `int16` | `int32` | `int64` | `uint8` | `uint16` | `uint32` | `uint64` | `logical` | `char` | `datetime` | `duration` | `table` | `timetable`

Dimension to operate along, specified as a positive integer scalar. If you do not specify the dimension, then the default is the first array dimension of size greater than 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 an `m`-by-`n` input matrix, `A`:

• `mean(A,1)` computes the mean of the elements in each column of `A` and returns a `1`-by-`n` row vector. • `mean(A,2)` computes the mean of the elements in each row of `A` and returns an `m`-by-`1` column vector. `mean` returns `A` when `dim` is greater than `ndims(A)` or when `size(A,dim)` is `1`.

Vector of dimensions, specified as a vector of positive integers. Each element represents a dimension of the input array. The lengths of the output in the specified operating dimensions are 1, while the others remain the same.

Consider a 2-by-3-by-3 input array, `A`. Then `mean(A,[1 2])` returns a 1-by-1-by-3 array whose elements are the means over each page of `A`. Output data type, specified as one of the values in this table. These options also specify the data type in which the operation is performed.

`outtype`Output data type
`"default"``double`, unless the input data type is `single`, `duration`, `datetime`, `table`, or `timetable`, in which case, the output is `"native"`
`"double"``double`, unless the data input type is `duration`, `datetime`, `table`, or `timetable`, in which case, `"double"` is not supported
`"native"`

Same data type as the input, unless:

• Input data type is `logical`, in which case, the output is `double`

• Input data type is `char`, in which case, `"native"` is not supported

• Input data type is `timetable`, in which case, the output is `table`

Missing value condition, specified as one of the values in this table.

ValueInput Data TypeDescription
`"includemissing"`All supported data types

Include missing values in `A` when computing the mean. If any element in the operating dimension is missing, then the corresponding element in `M` is missing.

`"includenan"``double`, `single`, `duration`
`"includenat"``datetime`
`"omitmissing"`All supported data typesIgnore missing values in `A`, and compute the mean over fewer points. If all elements in the operating dimension are missing, then the corresponding element in `M` is missing.
`"omitnan"``double`, `single`, `duration`
`"omitnat"``datetime`

collapse all

### Mean

For a finite-length vector A made up of N scalar observations, the mean is defined as

`$\mu =\frac{1}{N}\sum _{i=1}^{N}{A}_{i}.$`

## Version History

Introduced before R2006a

expand all