Description of Map Class

A Map is actually an object, or instance, of a MATLAB^® class called Map. It is also a handle object and, as such, it behaves like any other MATLAB handle object. This section gives a brief overview of the Map class. For more details, see the containers.Map reference page.

Properties of Map Class

All objects of the Map class have three properties. You cannot write directly to any of these properties; you can change them only by means of the methods of the Map class.

Property	Description	Default
`Count`	Unsigned 64-bit integer that represents the total number of key/value pairs contained in the `Map` object.	0
`KeyType`	Character vector that indicates the type of all keys contained in the `Map` object. `KeyType` can be any of the following: `double`, `single`, `char`, and signed or unsigned 32-bit or 64-bit integer. If you attempt to add keys of an unsupported type, `int8` for example, MATLAB makes them `double`.	`char`
`ValueType`	Character vector that indicates the type of values contained in the `Map` object. If the values in a Map are all scalar numbers of the same type, `ValueType` is set to that type. If the values are all character arrays, `ValueType` is `'char'`. Otherwise, `ValueType` is `'any'`.	`any`

To examine one of these properties, follow the name of the Map object with a dot and then the property name. For example, to see what type of keys are used in Map mapObj, use

mapObj.KeyType

A Map is a handle object. As such, if you make a copy of the object, MATLAB does not create a new Map; it creates a new handle for the existing Map that you specify. If you alter the Map's contents in reference to this new handle, MATLAB applies the changes you make to the original Map as well. You can, however, delete the new handle without affecting the original Map.

Methods of Map Class

The Map class implements the following methods. Their use is explained in the later sections of this documentation and also in the function reference pages.

Method	Description
`isKey`	Check if Map contains specified key
`keys`	Names of all keys in Map
`length`	Length of Map
`remove`	Remove key and its value from Map
`size`	Dimensions of Map
`values`	Values contained in Map