The lowerEntry() method of NavigableMap interface in Java is used to return a key-value mapping associated with the greatest key strictly less than the given key, or null if there is no such key existed.
Syntax:
Map.Entry< K, V > lowerEntry(K key)
Where, K is the type of key maintained by this map and V is the type of values mapped to the keys.
Parameters: This function accepts a single parameter Key which refers to the type of key maintained by this map container.
Return Value: It returns a key-value mapping associated with the greatest key strictly less than the given key, or null if there is no such key existed.
Below programs illustrate the lowerEntry() method in Java:
Program 1: When the key is integer.
// Java code to demonstrate the working of// lowerEntry() method import java.io.*;import java.util.*; public class GFG { public static void main(String[] args) { // Declaring the NavigableMap of Integer and String NavigableMap<Integer, String> nmmp = new TreeMap<>(); // assigning the values in the NavigableMap // using put() nmmp.put(2, "two"); nmmp.put(7, "seven"); nmmp.put(3, "three"); System.out.println("The mapping with greatest key strictly" + " less than 7 is : " + nmmp.lowerEntry(7)); }} |
The mapping with greatest key strictly less than 7 is : 3=three
Program 2: When the key is string.
// Java code to demonstrate the working of// lowerEntry() method import java.io.*;import java.util.*; public class GFG { public static void main(String[] args) { // Declaring the NavigableMap of Integer and String NavigableMap<String, String> tmmp = new TreeMap<>(); // assigning the values in the NavigableMap // using put() tmmp.put("one", "two"); tmmp.put("six", "seven"); tmmp.put("two", "three"); System.out.println("The mapping with greatest key strictly" + " less than 7 is : " + tmmp.lowerEntry("two")); }} |
The mapping with greatest key strictly less than 7 is : six=seven
Reference: https://docs.oracle.com/javase/10/docs/api/java/util/NavigableMap.html#lowerEntry(K)
