print map in java
map.forEach((key, value) -> System.out.println(key + ":" + value));
3.33
3
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.stream.Stream;
class MapUtil
{
// Program to print all keys present in the Map using keySet() in Java
public static void main (String[] args)
{
Map<Integer, String> map = new HashMap<>();
map.put(1, "One");
map.put(2, "Two");
// 1. using Iterator
Iterator<Integer> itr = map.keySet().iterator();
while (itr.hasNext()) {
System.out.println(itr.next());
}
// 2. For-each Loop
for (Integer key : map.keySet()) {
System.out.println(key);
}
// 3. Java 8 - Collection.iterator() + Iterator.forEachRemaining()
map.keySet().iterator()
.forEachRemaining(System.out::println);
// 4. Java 8 - Collection.stream() + Stream.forEach()
map.keySet().stream()
.forEach(System.out::println);
// Java 8 - Stream.of() + Collection.toArray() + Stream.forEach()
Stream.of(map.keySet().toArray())
.forEach(System.out::println);
// 5. Convert to String
System.out.println(map.keySet().toString());
// Java 8
Stream.of(map.keySet().toString())
.forEach(System.out::println);
}
}
Thank you!
3
0
4
1
// Java 8 - Collection.iterator() + Iterator.forEachRemaining()
map.keySet().iterator()
.forEachRemaining(System.out::println);
Thank you!
1
0
4.1
10
import java.util.HashMap;
import java.util.Map;
import java.util.Iterator;
import java.util.Set;
public class Details {
public static void main(String args[]) {
/* This is how to declare HashMap */
HashMap<Integer, String> hmap = new HashMap<Integer, String>();
/*Adding elements to HashMap*/
hmap.put(12, "Chaitanya");
hmap.put(2, "Rahul");
hmap.put(7, "Singh");
hmap.put(49, "Ajeet");
hmap.put(3, "Anuj");
/* Display content using Iterator*/
Set set = hmap.entrySet();
Iterator iterator = set.iterator();
while(iterator.hasNext()) {
Map.Entry mentry = (Map.Entry)iterator.next();
System.out.print("key is: "+ mentry.getKey() + " & Value is: ");
System.out.println(mentry.getValue());
}
/* Get values based on key*/
String var= hmap.get(2);
System.out.println("Value at index 2 is: "+var);
/* Remove values based on key*/
hmap.remove(3);
System.out.println("Map key and values after removal:");
Set set2 = hmap.entrySet();
Iterator iterator2 = set2.iterator();
while(iterator2.hasNext()) {
Map.Entry mentry2 = (Map.Entry)iterator2.next();
System.out.print("Key is: "+mentry2.getKey() + " & Value is: ");
System.out.println(mentry2.getValue());
}
}
}
Thank you!
10
0
4.45
10
Map<String, Integer> map = new HashMap<>();
map.put("a", 1);
map.put("b", 2);
System.out.println(Arrays.asList(map)); // method 1
System.out.println(Collections.singletonList(map)); // method 2
Thank you!
10
0
0
9
// 1. for-each with Entry
Map<Integer, Integer> map = new HashMap<Integer, Integer>();
for (Map.Entry<Integer, Integer> entry : map.entrySet()) {
System.out.println("Key = " + entry.getKey() + ", Value = " + entry.getValue());
}
// 2. for-each with key or value each (faster)
Map<Integer, Integer> map = new HashMap<Integer, Integer>();
//iterating over keys only
for (Integer key : map.keySet()) {
System.out.println("Key = " + key);
}
//iterating over values only
for (Integer value : map.values()) {
System.out.println("Value = " + value);
}
// 3. Using Iterator
Map<Integer, Integer> map = new HashMap<Integer, Integer>();
// With Generic
Iterator<Map.Entry<Integer, Integer>> entries = map.entrySet().iterator();
while (entries.hasNext()) {
Map.Entry<Integer, Integer> entry = entries.next();
System.out.println("Key = " + entry.getKey() + ", Value = " + entry.getValue());
}
// No Generic
Map map = new HashMap();
Iterator entries = map.entrySet().iterator();
while (entries.hasNext()) {
Map.Entry entry = (Map.Entry) entries.next();
Integer key = (Integer)entry.getKey();
Integer value = (Integer)entry.getValue();
System.out.println("Key = " + key + ", Value = " + value);
}
Thank you!
9
0
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