How do I use a map in salesforce?

What is a Map in Salesforce?

Ans - a. Map Collection allows us to store Key-Value pairs.

b. Map is an Unordered Collection.

c. In Map, the Key is Unique and Value is Unique or Duplicate.

d. In Map, every element is identified using a Key.

e. Map Class doesn't allow duplicate elements.

Syntax of Map Class -

Map<Key Datatype, Value Datatype> objectName = new Map<Key Datatype, Value Datatype>();

e.g. -

Map<Integer, Integer> customerCodes = new Map<Integer, Integer>();

Methods in Map Class -

1. Put(Key, Value) - used to add a new element inside the collection.

2. PutAll(map_collection) - used to add a collection of elements to the map collection at a time.

3. size() - it returns the size of the collection.

4. isEmpty() - used to check collection is empty or not.

5. Get(KeyName) - used to get the value of a specified key.

6. ContainsKey(KeyName) - used to Find the element in Collection.

7. Remove(KeyName) - used to remove a specified element from the collection.

8. Clear() - used to remove all elements from the Set.

9. Equals(sourceCollection) - used to compare two collections.

10. Set<Datatype> KeySet() - it returns all the key which is present in the collection.

11. List<Datatype> Values() - it returns all the Values which is present in the collection.

e.g. -

Map<string, integer=" "> carPrice = new Map<string, integer=" ">();

carPrice.put('Swift', 900000);

carPrice.put('Honda City', 1200000);

carPrice.put('Scorpio', 1600000);

carPrice.put('xuv', 2200000);

System.debug('List of Car Price is=' +carPrice); </string>

System.debug('Total Number of Car in Collection is:' +carPrice.size());

integer carModel = carPrice.get('swift');

system.debug('The swift price is = ' + carModel );

string carName = carPrice.get(2200000);

system.debug('2200000 is the price of Car = ' + carName );