Java uses the stream() function of the Arrays class to convert an array into a stream

Java uses the stream() function of the Arrays class to convert an array into a stream

In Java programming, it is often necessary to perform various operations and processing on arrays. With the release of Java 8, the concept of flow programming was introduced, making array processing more flexible and concise. The stream() function in the Arrays class is one of them. It can convert an array into a stream object, thereby conveniently performing various streaming operations.

The so-called stream means that data is transmitted in a continuous manner, and various processing such as filtering, calculation, and mapping can be performed on it. For arrays, using streams for processing can greatly simplify the code and improve development efficiency. The following will introduce in detail how to use the stream() function of the Arrays class to convert an array into a stream, and show some example code.

First, we need to import the java.util.Arrays class.

import java.util.Arrays;

Secondly, define an array as our data source. Here we take an integer array as an example.

int[] nums = {1, 2, 3, 4, 5};

Next, use the stream() function of the Arrays class to convert the array into a stream.

Stream stream = Arrays.stream(nums);

In this way, we get a stream object stream, which can be used for various operations.

For example, you can use the forEach() function to traverse the stream and operate on each element.

stream.forEach(System.out::println);

In the above code, the println() method of the System class is referenced through the :: operator to output each element to the control tower.

In addition, we can also perform filtering, calculation, mapping and other operations.

For example, you can use the filter() function to filter the stream and only retain elements that meet the conditions.

stream.filter(n -> n % 2 == 0)

  .forEach(System.out::println);

In the above code, the filter() function is used to retain the even numbers in the array and output them to the console.

For another example, you can use the map() function to map each element in the stream.

stream.map(n -> n * n)

  .forEach(System.out::println);

In the above code, use the map() function to square each element in the array and output it to the console .

In addition to common operations, we can also use the reduce() function to perform reduction operations on streams.

int sum = stream.reduce(0, (a, b) -> a b);
System.out.println(sum);

In the above code, reduce( ) function accepts two parameters, the first parameter is the initial value of the reduction, and the second parameter is a binary operation used to reduce the elements in the stream. The binary operation used here is to add two numbers. Finally, the elements in the array are added to get the sum and output to the console.

It should be noted that the stream can only be consumed once, that is to say, the above operation can only be performed once. If you want to perform multiple operations on the same stream, you should recreate the stream object.

To sum up, using the stream() function of the Arrays class in Java to convert an array into a stream is a very convenient and practical method. Through flow programming, the efficiency of array operation and processing can be greatly improved, while also making the code more concise and readable. Hope the above code example is helpful to readers.

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