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Learn_Map.java
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Learn_Map.java
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package Java_Collections_Framework;
// we can store key value pair in it and all the keys are unique, & Values may be or may not be Unique but keys are
// always unique.
import java.util.*;
public class Learn_Map {
public static void main(String[] args) {
// Map<String,Integer>num=new HashMap<>(); // Unordered key value pair
Map<String,Integer>num=new TreeMap<>(); // it isb used for a sorted manner and ordered pair
num.put("One",1);
num.put("Two",2);
num.put("Three",3);
num.put("Four",4);
num.put("Five",5);
num.remove("Three");
//System.out.println(num);
//if(!num.containsKey("Five")){ // if statement check value is present or not in map containsKey check value
// num.put("Five",32);
//}
num.putIfAbsent("Five",32); // same as if statement
// num.put("Five",32); // override the key pair value mean update
System.out.println(num);
for(Map.Entry<String,Integer>e:num.entrySet()) {
System.out.println(e);
System.out.println(e.getKey());
System.out.println(e.getValue());
}
for(String key:num.keySet()){
System.out.println(key);
}
for(Integer value:num.values()){
System.out.println(value);
}
System.out.println(num.containsValue(3));
System.out.println(num.isEmpty());
}
}