MATLAB Programming Fundamentals - MathWorks

Create Map Object

A Map is an object of the Map class. It is defined within a MATLAB package called

containers. As with any class, you use its constructor function to create any new

instances of it. You must include the package name when calling the constructor:

newMap = containers.Map(optional_keys_and_values)

Construct Empty Map Object

When you call the Map constructor with no input arguments, MATLAB constructs an

empty Map object. When you do not end the command with a semicolon, MATLAB displays

the following information about the object you have constructed:

newMap = containers.Map

newMap =

Map with properties:

Count: 0

KeyType: char

ValueType: any

The properties of an empty Map object are set to their default values:

• Count = 0


• KeyType = 'char'


• ValueType = 'any'

Once you construct the empty Map object, you can use the keys and values methods to

populate it. For a summary of MATLAB functions you can use with a Map object, see

“Methods of Map Class” on page 14-5

Construct Initialized Map Object

Most of the time, you will want to initialize the Map with at least some keys and values at

the time you construct it. You can enter one or more sets of keys and values using the

syntax shown here. The brace operators ({}) are not required if you enter only one key/

value pair:

14 Map Containers