check if map contains key java
if (map.containsKey(key)) {
// Okay, there's a key but the value is null
} else {
// Definitely no such key
}check if map contains key java
if (map.containsKey(key)) {
// Okay, there's a key but the value is null
} else {
// Definitely no such key
}map java
import java.util.HashMap;
import java.util.Iterator;
import java.util.LinkedHashMap;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Set;
public class Main {
public static void main(String[] args) {
//La fameuse syntaxe en diamant de Java 7
Map<Integer, String> hm = new HashMap<>();
hm.put(10, "1");
hm.put(20, "2");
hm.put(30, "3");
hm.put(40, "4");
hm.put(50, "5");
//Ceci va écraser la valeur 5
hm.put(50, "6");
System.out.println("Parcours de l'objet HashMap : ");
Set<Entry<Integer, String>> setHm = hm.entrySet();
Iterator<Entry<Integer, String>> it = setHm.iterator();
while(it.hasNext()){
Entry<Integer, String> e = it.next();
System.out.println(e.getKey() + " : " + e.getValue());
}
System.out.println("Valeur pour la clé 8 : " + hm.get(8));
Map<Integer, String> lhm = new LinkedHashMap<>();
lhm.put(10, "1");
lhm.put(20, "2");
lhm.put(30, "3");
lhm.put(40, "4");
lhm.put(50, "5");
System.out.println("Parcours de l'objet LinkedHashMap : ");
Set<Entry<Integer, String>> setLhm = lhm.entrySet();
Iterator<Entry<Integer, String>> it2 = setLhm.iterator();
while(it2.hasNext()){
Entry<Integer, String> e = it2.next();
System.out.println(e.getKey() + " : " + e.getValue());
}
}
}Copyright © 2021 Codeinu
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