Question

我知道有些人已经问过重复项，我已经查看了所有这些答案，但似乎没有人帮助我/我仍然无法编译。我的代码中是否有一些我不知道的东西？帮助（编程新手！）

我需要编写一个方法，该方法接受一个参数，一个String值数组，并返回一个没有重复值且不需要对原始数组进行排序的新数组。例如

String [] abc = {"A", "C", "C", "B", "A", "C", "B", "B", "A"};
String [] new = removeDuplicates (abc);
for (int i = 0; i < new.length; i++)
{
    System.out.print (new[i] + " ");
}
System.out.println();

输出应为：A C B

这是我的代码：

    import java.util.*;

    class Duplication
    {
        public static void main (String [] args)
        {
            String [] values = {"A", "C", "C", "B", "A", "C", "B", "B", "A"};
            String [] newList = removeDuplicates (values);
        }
        private static String removeDuplicates (String [] originalArray)
        {
            for (int i = 0; i < newList.length; i++)
            {
                System.out.print (newList[i] + " ");
            }
            System.out.println();

            String noDuplicates = originalArray.length;
            for (int d = 0; d < noDuplicates; d++)
            {
                for (int e = d + 1; e < noDuplicates; e++)
                {
                    if(originalArray[d] == originalArray[e])
                    {
                        originalArray[e] = originalArray[noDuplicates-1];
                        noDuplicates--;
                        e--;
                    }
                }
            }
        }  
    }

六个错误：

    Duplication.java:9: error: incompatible types
    String [] newList = removeDuplicates (values);
                                     ^
    required: String[]
    found:    String
    Duplication.java:14: error: cannot find symbol
    for (int i = 0; i < newList.length; i++)
                        ^
    symbol:   variable newList
    location: class Duplicates
    Duplication.java:16: error: cannot find symbol
        System.out.print (newList[i] + " ");
                          ^
    symbol:   variable newList
    location: class Duplicates
    Duplication.java:21: error: incompatible types
    String noDuplicates = originalArray.length;
                                       ^
    required: String
    found:    int
    Duplication.java:32: error: bad operand types for binary operator '-'
                originalArray[e] = originalArray[noDuplicates-1];
                                                             ^
    first type:  String
    second type: int
    Duplication.java:35: error: bad operand type String for unary operator '--'
                noDuplicates--;
                            ^

Answer 1

这在java中无效：

public static void main (String [] args)
String [] values = {"A", "C", "C", "B", "A", "C", "B", "B", "A"};
String [] newList = removeDuplicates (values);

你必须添加 {} 来定义静态main方法的范围：

public static void main (String [] args){
      String[] values = {"A", "C", "C", "B", "A", "C", "B", "B", "A"};
      String[] newList = removeDuplicates (values);
}

Answer 2

1）你的方法removeDuplicates（）返回一个String。在主块中，您需要一个String数组。

2）范围变量newList在主块内。因此，此方法在removeDuplicates

方法中不可见

3）“originalArray.length”返回“int”，而不是String。

Answer 3

您应该阅读错误消息。

 Duplication.java:9: error: incompatible types
 String [] newList = removeDuplicates (values);

此函数返回String不是String []

的

 private static String removeDuplicates (String [] originalArray)

 private static String [] removeDuplicates (String [] originalArray)

您应该将其声明为

newList

您应该在函数范围内声明Duplication.java:14: error: cannot find symbol for (int i = 0; i < newList.length; i++)以使用它，这会导致

int noDuplicates = originalArray.length;

长度是整数，应按如下方式处理：

SELECT person_name
FROM person
WHERE person_id IN
(SELECT Person_Person_Id
FROM customer);

仔细阅读编译错误，它们可以解决所有问题。

Answer 4

这就是你需要的所有代码。您可以在此处阅读这些馆藏https://docs.oracle.com/javase/tutorial/collections/

import java.util.*;

    class Duplication
    {
        static String [] values = {"A", "C", "C", "B", "A", "C", "B", "B", "A"};
        public static void main (String [] args){
            System.out.println(removeDuplicates(values));

        }
        static Set removeDuplicates(String [] originalArray)
        {
            List arList = new ArrayList<String>(Arrays.asList(values));
            return new LinkedHashSet<String>(arList);
        }  
    }

Java - 从数组中删除重复元素时出错

4 个答案: