Java Arrays.sort()用法及代碼示例

sort()方法是java.util.Arrays類方法。句法：

public static void sort(int[] arr, int from_Index, int to_Index)

arr - the array to be sorted
from_Index - the index of the first element, inclusive, to be sorted
to_Index - the index of the last element, exclusive, to be sorted

This method doesn't return any value.

一個Java程序，用於按升序對整數數組進行排序。

Java

// A sample Java program to sort an array of integers
// using Arrays.sort(). It by default sorts in
// ascending order
import java.util.Arrays;
 
public class SortExample
{
    public static void main(String[] args)
    {
        // Our arr contains 8 elements
        int[] arr = {13, 7, 6, 45, 21, 9, 101, 102};
 
        Arrays.sort(arr);
 
        System.out.printf("Modified arr[]:%s",
                          Arrays.toString(arr));
    }
}

輸出：

Modified arr[]:[6, 7, 9, 13, 21, 45, 101, 102]

我們還可以使用sort()對arr []的子數組進行排序

Java

// A sample Java program to sort a subarray
// using Arrays.sort().
import java.util.Arrays;
 
public class SortExample
{
    public static void main(String[] args)
    {
        // Our arr contains 8 elements
        int[] arr = {13, 7, 6, 45, 21, 9, 2, 100};
 
        // Sort subarray from index 1 to 4, i.e.,
        // only sort subarray {7, 6, 45, 21} and
        // keep other elements as it is.
        Arrays.sort(arr, 1, 5);
 
        System.out.printf("Modified arr[]:%s",
                          Arrays.toString(arr));
    }
}

輸出：

Modified arr[]:[13, 6, 7, 21, 45, 9, 2, 100]

我們還可以按降序排序。

Java

// A sample Java program to sort a subarray
// in descending order using Arrays.sort().
import java.util.Arrays;
import java.util.Collections;
 
public class SortExample
{
    public static void main(String[] args)
    {
        // Note that we have Integer here instead of
        // int[] as Collections.reverseOrder doesn't
        // work for primitive types.
        Integer[] arr = {13, 7, 6, 45, 21, 9, 2, 100};
 
        // Sorts arr[] in descending order
        Arrays.sort(arr, Collections.reverseOrder());
 
        System.out.printf("Modified arr[]:%s",
                          Arrays.toString(arr));
    }
}

輸出：

Modified arr[]:[100, 45, 21, 13, 9, 7, 6, 2]

我們還可以按字母順序對字符串進行排序。

Java

// A sample Java program to sort an array of strings
// in ascending and descending orders using Arrays.sort().
import java.util.Arrays;
import java.util.Collections;
 
public class SortExample
{
    public static void main(String[] args)
    {
        String arr[] = {"practice.geeksforgeeks.org",
                        "quiz.geeksforgeeks.org",
                        "code.geeksforgeeks.org"
                       };
 
        // Sorts arr[] in ascending order
        Arrays.sort(arr);
        System.out.printf("Modified arr[]:\n%s\n\n",
                          Arrays.toString(arr));
 
        // Sorts arr[] in descending order
        Arrays.sort(arr, Collections.reverseOrder());
 
        System.out.printf("Modified arr[]:\n%s\n\n",
                          Arrays.toString(arr));
    }
}

輸出：

Modified arr[]:


Modified arr[]:
[quiz.geeksforgeeks.org, practice.geeksforgeeks.org, code.geeksforgeeks.org]

我們還可以根據用戶定義的標準對數組進行排序。
為此，我們使用比較器接口。下麵是一個例子。

Java

// Java program to demonstrate working of Comparator
// interface
import java.util.*;
import java.lang.*;
import java.io.*;
 
// A class to represent a student.
class Student
{
    int rollno;
    String name, address;
 
    // Constructor
    public Student(int rollno, String name,
                               String address)
    {
        this.rollno = rollno;
        this.name = name;
        this.address = address;
    }
 
    // Used to print student details in main()
    public String toString()
    {
        return this.rollno + " " + this.name +
                           " " + this.address;
    }
}
 
class Sortbyroll implements Comparator<Student>
{
    // Used for sorting in ascending order of
    // roll number
    public int compare(Student a, Student b)
    {
        return a.rollno - b.rollno;
    }
}
 
// Driver class
class Main
{
    public static void main (String[] args)
    {
        Student [] arr = {new Student(111, "bbbb", "london"),
                          new Student(131, "aaaa", "nyc"),
                          new Student(121, "cccc", "jaipur")};
 
        System.out.println("Unsorted");
        for (int i=0; i<arr.length; i++)
            System.out.println(arr[i]);
 
        Arrays.sort(arr, new Sortbyroll());
 
        System.out.println("\nSorted by rollno");
        for (int i=0; i<arr.length; i++)
            System.out.println(arr[i]);
    }
}

輸出：

Unsorted
111 bbbb london
131 aaaa nyc
121 cccc jaipur

Sorted by rollno
111 bbbb london
121 cccc jaipur
131 aaaa nyc

相關用法

注：本文由純淨天空篩選整理自GeeksforGeeks大神的英文原創作品 Arrays.sort() in Java with examples。非經特殊聲明，原始代碼版權歸原作者所有，本譯文未經允許或授權，請勿轉載或複製。