EN
Java - get keys and values from HashMap
2 points
Short solution - get all keys and values
xxxxxxxxxx1
Map<String, Integer> map = new HashMap<>();2
3
for (Map.Entry<String, Integer> entry : map.entrySet()) {4
5
String key = entry.getKey();6
Integer value = entry.getValue();7
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System.out.println("Key: " + key + ", Value : " + value);9
}Short solution - get only keys
xxxxxxxxxx1
Map<String, Integer> map = new HashMap<>();2
Set<String> keys = map.keySet();3
4
for (String key : keys) {5
System.out.println("Key: " + key);6
}Short solution - get only values
xxxxxxxxxx1
Map<String, Integer> map = new HashMap<>();2
Collection<Integer> values = map.values();3
4
for (Integer value : values) {5
System.out.println("Value: " + value);6
}Short solution - get all keys and values - Java 8
xxxxxxxxxx1
Map<String, Integer> map = new HashMap<>();2
3
map.forEach((key, value) -> {4
// use key and value variables5
System.out.println("Key: " + key + ", Value : " + value);6
});xxxxxxxxxx1
import java.util.HashMap;2
import java.util.Map;3
4
public class Example1 {5
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public static void main(String[] args) {7
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Map<String, Integer> map = new HashMap<>();9
map.put("A", 10);10
map.put("B", 20);11
map.put("C", 30);12
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for (Map.Entry<String, Integer> entry : map.entrySet()) {14
15
String key = entry.getKey();16
Integer value = entry.getValue();17
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System.out.println("Key: " + key + ", Value : " + value);19
}20
}21
}Output:
xxxxxxxxxx1
Key: A, Value : 102
Key: B, Value : 203
Key: C, Value : 30xxxxxxxxxx1
import java.util.HashMap;2
import java.util.Map;3
import java.util.Set;4
5
public class Example2 {6
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public static void main(String[] args) {8
9
Map<String, Integer> map = new HashMap<>();10
map.put("A", 10);11
map.put("B", 20);12
map.put("C", 30);13
14
Set<String> keys = map.keySet();15
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for (String key : keys) {17
System.out.println("Key: " + key);18
}19
}20
}Output:
xxxxxxxxxx1
Key: A2
Key: B3
Key: Cxxxxxxxxxx1
import java.util.Collection;2
import java.util.HashMap;3
import java.util.Map;4
5
public class Example3 {6
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public static void main(String[] args) {8
9
Map<String, Integer> map = new HashMap<>();10
map.put("A", 10);11
map.put("B", 20);12
map.put("C", 30);13
14
Collection<Integer> values = map.values();15
16
for (Integer value : values) {17
System.out.println("Value: " + value);18
}19
}20
}Output:
xxxxxxxxxx1
Value: 102
Value: 203
Value: 30xxxxxxxxxx1
import java.util.HashMap;2
import java.util.Map;3
4
public class Example4 {5
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public static void main(String[] args) {7
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Map<String, Integer> map = new HashMap<>();9
map.put("A", 10);10
map.put("B", 20);11
map.put("C", 30);12
13
map.forEach((key, value) -> {14
// use key and value variables15
System.out.println("Key: " + key + ", Value : " + value);16
});17
}18
}Output:
xxxxxxxxxx1
Key: A, Value : 102
Key: B, Value : 203
Key: C, Value : 30
