Java HashMap replaceAll() Method
Example
Update the value of every entry in a map:
import java.util.HashMap;
public class Main {
public static void main(String[] args) {
HashMap<String, String> capitalCities = new HashMap<String, String>();
capitalCities.put("England", "London");
capitalCities.put("Germany", "Berlin");
capitalCities.put("Norway", "Oslo");
capitalCities.put("USA", "Washington DC");
capitalCities.replaceAll((k, v) -> "The capital of " + k + " is " + v);
System.out.println(capitalCities);
}
}
Definition and Usage
The replaceAll() method replaces the value of every entry in the map with the result of an operation using the entry's key and value. The operation can be defined by a lambda expression that is compatible with the apply() method of Java's BiFunction interface.
To learn about lambda expressions, see our Java Lambda Expression tutorial.
Syntax
public void replaceAll(BiFunction operator)Parameter Values
| Parameter | Description |
|---|---|
| operator |
Required. A BiFunction object or lambda expression which operates on each entry.The first parameter of the function contains the key of an entry and the second parameter contains its value. |
Related Pages
❮ HashMap Methods
