In Java, it is common to work with arrays and lists, and sometimes we need to convert an array into a list for easier manipulation and flexibility. An array can be converted to a List easily using multiple ways. Why Convert an Array to a List? Converting an array to a list allows us...
Here, we use thekeySet()method to get keys by creating an array list from a set returned by a map. Check out the following example, which converts a map into a list. Example 1: packagemaptolist;importjava.util.HashMap;importjava.util.List;importjava.util.Map;importjava.util.stream.Col...
Learn several ways to convert a List into a Map using Custom Suppliers. Read more→ Converting a List to String in Java Learn how to convert a List to a String using different techniques. Read more→ 2. Sample Data Structure First, we’ll model the element: publicclassAnimal{privateintid;...
String str = String.join(", ", set); Example Following is the program to convert set of string to a comma separated string in Java − import java.util.*; public class Demo { public static void main(String args[]) { Set<String>set = new HashSet<>(Arrays.asList("One", "Two",...
TheMap.keySet()returns aSetview of all the keys in theMap. Set<String>keySet=map.keySet(); 4. Conclusion This tutorial taught us how to convert Java Map keys and values into an Array, List or Set with simple examples. We learned to use theArrayListandHashSetconstructors as well as Str...
To convert an array to a Set in Java, you can use the Arrays.asList() method to create a List from the array, and then use the List.toSet() method to create a Set from the List. Here is an example of how to convert an array to a Set: import java.util.Arrays; import java....
However, we can convert a mutable collection into an immutable one when required. We’ve mentioned the handy extension functions earlier. For example, we can convert a List to Set by calling the list.toSet() method: assertThat(inputList.toSet()).isInstanceOf(LinkedHashSet::class.java).is...
ImmutableListMultimap<Integer,Employee>employeeMap=Multimaps.index(duplicateEmployeeList,Employee::id); 3. Conclusion We have learned the various ways by which we can convert a List into a Map in Java. We have covered both scenarios where a List contains unique elements as well as when aListcon...
At times it is needed to convert a string into a date format. The string may be a date value stored as a string in the database or a value returned from the API. In either case, this string value cannot be directly used in date pickers or input type date. Hence, the string will ...
ArrayUtils.toPrimitive()to Convert Integer List to Int Array in Java We have another way of casting aList<Integer>to anint[]type. We will use Apache Common Lang, which is a set of helper methods. ArrayUtils.toPrimitive()allows us to pass in ournumListthat gives us the result inint[]data...