How Important is to Know About the Map in Salesforce in 2020?

What exactly is a map in Salesforce?

The Map methods are all instance methods, that is, they operate on a particular instance of a map.

The following are the instance methods for maps:

What is a map?

• A map is a collection of key-value pairs where each unique key maps to a single value. In map Keys can be any primitive data type like string, integer,decimal, Id while values can be a primitive, sObject, collection type or an Apex object.
• Map keys and values can be of any data type—primitive types, collections, sObjects, user-defined types, and built-in Apex types.
• Map keys of type String are case-sensitive. Map methods, including put, get, containsKey, and remove treat these keys as distinct.
• The map gives value on the basis of key.
• Key is always unique but a value can be duplicated.

Syntax

Map<integer, string>exMap= new map<integer, string>();
exMap.put(1,'James');
exMap.put(2,'Daniel');
exMap.put(3,'Peter');
string name= exMap.get(1);
string name1= exMap.get(2);
string name2= exMap.get(3);
system.debug(name);//James
system.debug(name1);//Daniel
system.debug(name2);// Peter
set<integer>key= exmap.keyset();
list<string>values=exmap.values();
system.debug(values);//James, Daniel, Peter

Once you’re familiar with the syntax and the fundamentals of Salesforce, mapping with it becomes simpler. Learn more with our Self-learning module.

Read: How To Create a Custom Object TABS In Salesforce.Com?

Map Methods

The following are methods for Map. All are instance methods.

• clear() Removes all of the key-value mappings from the map.
• clone() Makes a duplicate copy of the map.
• containsKey(key) This method returns true if the map contains - the  If the key is a string, the key value is case-sensitive.
• deepClone() DeepClone () method creates a duplicate copy of a map, including sObject records if the map has sObject record values .
• equals(map2) It compares a map with a specified map and returns true if both maps are equal; otherwise, returns false.
• get(key) This method returns the value of the specified key which is mapped, or it returns null if the map contains no value for this key.
• getSObjectType() This method returns the value of the sObject type in format of key and value.
• isEmpty() If the map has zero key-value pairs it returns true.
• keySet() Returns a set that contains all of the keys in the map.
• put(key, value):
• Associates the specified value with the specified key in the map.
• putAll(fromMap) Copies all of the mappings from the specified map to the original map.
• putAll(sobjectArray) Adds the list of sObject records to a map declared as Map<ID, sObject> or Map<String, sObject>.
• remove(key) This method removes the mapping for the specified key from the map, if present, and returns the corresponding value.
• size() Returns the number of key-value pairs in the map.
• values() This method returns a list which contains all the values in the map.The values are returned in an arbitrary order.

Read: What is Scheduled Apex in Salesforce?

get(key):

list<account>myAccounts = new list<account>();
myAccounts = [Select ID, Name from Account limit 10]; 
map<id,string>myAMap = new map<id,string>();
for ( Account a : myAccounts ){
//Here putting account Id and name to map
myAMap.put(a.ID, a.Name);
    } 
for ( ID aID : myAMap.keySet() ){
system.debug(loggingLevel.debug, myAMap.get(aID));
    }    

putAll(fromMap):

Map<String, String> map1 = new Map<String, String>();
map1.put('Red','LightRed');
Map<String, String> map2 = new Map<String, String>();
map2.put('Blue','DarkRed');
// Add map1 entries to map2
map2.putAll(map1);
System.debug(map2.values());//(LightRed, 'DarkRed')

remove(key):

Map<String, String>colorCodes =   new Map<String, String>();
colorCodes.put('Red', 'FF0000');
colorCodes.put('Blue', '0000A0');
colorCodes.put('Green', '0000A0');
System.debug('printing=== '+colorCodes);// Blue=0000A0, Green=0000A0, Red=FF0000
for(String key:colorCodes.keySet().clone()) {
colorCodes.remove('Green');
system.debug(colorCodes);// Blue=0000A0, Red=FF0000
}

Values ():

Map<String, String>colorCodes = new Map<String, String>();
colorCodes.put('FF0000', 'Red');
colorCodes.put('0000A0', 'Blue');
List<String> colors = new List<String>();
colors = colorCodes.values();
system.debug(colors);//(Red, Blue)

getSObjectType()

Map <id,Account>acctMap = new map<id,account>([select  name from  Account limit 10]);
for(string accValue:acctmap.keyset()){
system.debug(acctmap.get(accValue));
}

Example How to display record on basis of alphabet

Read: How to Prepare For Salesforce App Builder Certification?

Apex class
public class DynamicSearchExample {
public Map<string,list<account>>accountsMap {get; set;}
public List<selectoption> keys {get; set;}
public String selectedKey {get; set;}
public Map<string, account>accsByName {get; set;}
public Set<string>getMapKeys(){
returnaccountsMap.keySet();
    }
publicDynamicSearchExample(){
accsByName=new Map<string, account>();
        List<string>sortedKeys=new List<string>();
accountsMap=new Map<string, list<account>>();
accountsMap.put('All', new List<account>());
        List<account>accs=[select Name, industry,type,phone from Account order by Name asc];               
for (Account acc : accs){
accountsMap.get('All').add(acc);
            String start=acc.Name.substring(0,1);
            List<account>accsFromMap=accountsMap.get(start);
if (null==accsFromMap){
accsFromMap=new List<account>();
accountsMap.put(start,accsFromMap);
            }
accsFromMap.add(acc);
accsByName.put(acc.name,acc);
        }
keys=new List<selectoption>();
for (String key : accountsMap.keySet()){
if(key != 'All'){
sortedKeys.add(key);
            }
        }
sortedKeys.sort();
sortedKeys.add('All');
for (String key : sortedKeys){
keys.add(new SelectOption(key, key));
        }
selectedKey='All';
    }
}
Visualforce page
<apex:page controller="DynamicSearchExample">
<img src="data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7" data-wp-preserve="%3Cscript%3E%0Afunctionredraw_accounts()%7B%0A%0A%20%20%20%20%7D%0A%3C%2Fscript%3E" data-mce-resize="false" data-mce-placeholder="1" class="mce-object" width="20" height="20" alt="&lt;script&gt;" title="&lt;script&gt;" />
<apex:form>
<apex:actionFunction name="redraw_accounts" rerender="accs" status="status"/>
<apex:pageBlock title="Criteria">
<apex:outputLabel value="Starting Letter"/>
<apex:selectList value="{!selectedKey}" size="1" onchange="redraw_accounts()">
<apex:selectOptions value="{!keys}" />
</apex:selectList>
</apex:pageBlock>
<apex:pageBlock title="Accounts">
<apex:actionstatus id="status" startText="Loading Data..........." stopText="Loading completed....." >
<apex:facet name="start"/>
<apex:facet name="stop">
<apex:outputPanel id="accs">
<apex:pageBlockTable value="{!accountsMap[selectedKey]}" var="acc">
<apex:column value="{!acc.name}"/>
<apex:column value="{!acc.industry}"/>
<apex:column value="{!acc.type}"/>
<apex:column value="{!acc.phone}"/>
</apex:pageBlockTable>
</apex:outputPanel>
</apex:facet>
</apex:actionstatus>
</apex:pageBlock>
</apex:form>
</apex:page>

Output

Summary

The reason why maps are essential to use in Salesforce is that it makes it easy for writing the bulk apex class or trigger. As a beginner of Salesforce, we are unaware of various techniques using that we can employ script statements. You can learn more on maps in Salesforce by signing up with JanBask Training. Happy mapping to the happy people!