java stream findfirst vs findany

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java stream findfirst vs findany

The Stream interface in Java 8 provides several intermediate and terminal operations that allow you to perform various operations on a stream of elements, such as filtering, mapping, reducing, or finding elements.

Two of these terminal operations are findFirst and findAny, which allow you to find the first or any element in a stream that matches a given predicate, respectively.

Here is an example of how to use the findFirst operation to find the first element in a stream that matches a given predicate:

List<String> list = Arrays.asList("apple", "banana", "cherry", "date");

Optional<String> result = list.stream()
  .filter(s -> s.startsWith("c"))
  .findFirst();

System.out.println(result); // Outputs: Optional[cherry]

In this example, the list variable is defined as a list of strings, and the stream method is used to create a stream from the list. The filter operation is used to filter the stream to include only elements that start with the letter "c", and the findFirst operation is used to find the first element in the filtered stream. The result of the findFirst operation is wrapped in an Optional object, which is a container object that may or may not contain a non-null value.

The findFirst operation returns the first element in the stream that matches the predicate, or an empty Optional object if no such element is found. You can use the isPresent method of the Optional object to check whether a value is present, and the get method to retrieve the value.

Here is an example of how to use the findAny operation to find any element in a stream that matches a given predicate:

List<String> list = Arrays.asList("apple", "banana", "cherry", "date");

Optional<String> result = list.stream()
  .filter(s -> s.startsWith("c"))
  .findAny();

System.out.println(result); // Outputs: Optional[cherry]

The findAny operation is similar to the findFirst operation, but it is designed to be used in parallel streams, where the order of the elements is not guaranteed. The findAny operation returns any element in the stream that matches the predicate, or an empty Optional object if no such element is found.

You can use the findFirst and findAny operations to find elements in a stream that match a given predicate. The findFirst operation returns the first element that matches the predicate, while the findAny operation returns any element that matches the predicate, and is designed for use in parallel streams. You can customize these operations by specifying different predicates to match different elements in the stream.

Created Time:2017-11-01 22:29:55  Author:lautturi