# size

Size of `Map` object

## Syntax

``n = size(M,1)``
``szdim = size(M,dim)``
``sz = size(M)``
``[sz1,sz2,...,szL] = size(M)``

## Description

example

``` Note`dictionary` is recommended over `containers.Map` because it accepts more data types as keys and values and provides better performance. (since R2022b) `n = size(M,1)` returns the number of key-value pairs in the input `Map` object. `size(M,1)` is equivalent to `length(M)` and to the property `M.Count`.```
````szdim = size(M,dim)` returns the length of dimension `dim`. Since a `Map` object stores data as an `n`-by-`1` set of key-value pairs, `size` returns `1` when ```dim > 1```.```

example

````sz = size(M)` returns a two-element vector `[n 1]`, where `n` is the number of key-value pairs in `M`.```
````[sz1,sz2,...,szL] = size(M)` returns `[n,1,...,1]`.```

## Examples

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Create a `Map` object.

```months = {'Jan','Feb','Mar','Apr'}; rainfall = [327.2 368.2 197.6 178.4]; M = containers.Map(months,rainfall)```
```M = Map with properties: Count: 4 KeyType: char ValueType: double ```

Return the number of key-value pairs.

`n = size(M,1)`
```n = 4 ```

Return the number of pairs as a vector.

`sz = size(M)`
```sz = 1×2 4 1 ```

## Input Arguments

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Input `Map` object.

Queried dimension, specified as a positive numeric scalar.

## Version History

Introduced in R2008b