按名字和姓氏排序多维字符串数组

Question

我的一个Java类分配要求我对多维字符串数组进行排序。它还需要输入您是想按名字排序还是按姓氏排序。我不太理解这个问题的措辞，也就是主要的排序和粗体部分，所以我会把它贴在这里。

编写一个程序，使用以下标题对二维数组进行排序：

Public static void sort string ( nameSort [][]  )

该方法应先对行执行主排序，然后对列执行主排序。

使用以下数据测试您的程序：

{  
 {“Bill”,”Jones”}, 
 {“Janet”,”Kline”},
 {“George”,”Bailey”}, 
 {“Ellan”,”Sanches”}, 
 {“Tom”,”Nguyen”}, 
 {“William”,”Walters}, 
 {“Author”,”James”}, 
 {“Henry”,”Daniels”}, 
 {“Mike”,”Franklin”}, 
 {“Julie”,”Andrews"}
}

您的程序应该询问您是希望数组按名字排序还是按最后一个sName排序。

数组中的行将包含名字。sortArray中的列将包含姓氏。

Answer 1

以下是使用Java 8的最低限度代码：

    public static void sort2DArray(boolean sortByFirstName) {
        System.out.println("***** Sorting 2D Array *****");
        String[][] arr = {{"Bill","Jones"}, 
                            {"Janet","Kline"},
                            {"George","Bailey"}, 
                            {"Ellan","Sanches"}, 
                            {"Tom","Nguyen"}};
        List<String> l =  convertToList(arr);
        System.out.println("List = "+l.toString());
        if(sortByFirstName)
            Collections.sort(l, (s1, s2) -> s1.split(" ")[0].compareTo(s2.split(" ")[0]));
        else
            Collections.sort(l, (s1, s2) -> s1.split(" ")[1].compareTo(s2.split(" ")[1]));
        System.out.println("Sorted List = "+l.toString());


    }

    public static List<String> convertToList(String[][] arr){
        List<String> l8 = Arrays.asList(arr).stream().map(a -> a[0] + " "+ a[1]).collect(Collectors.toList());
        return l8;
    }

说明：1。首先将2D数组转换为字符串列表。

Answer 2

通过选择排序对名称进行排序，使用标志确定是否应按名字或姓氏排序。

public static void main(String[] args) {
   String[][] names = 
   {{"Bill","Jones"}, 
    {"Janet","Kline"},
    {"George","Bailey"}, 
    {"Ellan","Sanches"}, 
    {"Tom","Nguyen"}, 
    {"William","Walters"}, 
    {"Author","James"}, 
    {"Henry","Daniels"}, 
    {"Mike","Franklin"}, 
    {"Julie","Andrews"}};
   print(names);
   sortNames(names, true);
    System.out.println("-----");
    print(names);
}

public static void print(String[][] name) {
    int n = name.length;
    for (int i = 0; i < n; i++) {
        System.out.println(name[i][0] + " " + name[i][1]);
    }
}

private static void swap(String[][] name, int i, int j) {
    String firstName = name[i][0];
    String lastName = name[i][1];
    name[i][0] = name[j][0];
    name[j][0] = firstName;
    name[i][1] = name[j][1];
    name[j][1] = lastName;
}

public static void sortNames(String[][] name, boolean orderByFirst) {
    int n = name.length;      
    for (int i = 0; i < n - 1; i++) {
        int f = i;
        for (int j = i; j < n; j++) {
            // Sort on first name
            if (orderByFirst) {
                int compFirstName = name[f][0].compareTo(name[j][0]);
                if (compFirstName > 0) {
                    f = j;
                }
                // Same fist name, sort on last name
                else if (compFirstName == 0 && name[f][1].compareTo(name[j][1]) > 0) {
                    f = j;
                }
            } else {
               // sort by last name instead
               int comptLastName = name[f][1].compareTo(name[j][1]);
                if (comptLastName > 0) {
                    f = j;
                }
                // Same last name, sort on first name
                else if (comptLastName == 0 && name[f][0].compareTo(name[j][0]) > 0) {
                    f = j;
                }
            }
        }
        swap(name, i, f);
    }
}

输出（按名字排序）：

Author James
Bill Jones
Ellan Sanches
George Bailey
Henry Daniels
Janet Kline
Julie Andrews
Mike Franklin
Tom Nguyen
William Walters

输出（按姓氏排序）：

Julie Andrews
George Bailey
Henry Daniels
Mike Franklin
Author James
Bill Jones
Janet Kline
Tom Nguyen
Ellan Sanches
William Walters

Answer 3

根据我对这个问题的理解，这个问题只是要求您编写一个程序，根据名字或姓氏对数组进行排序，以数组的形式分别提供这两个字段。

不过，这个问题的措辞很奇怪。我认为“行和列”实际上是指“数组的第一个和第二个元素”。我找不到更好的解释。

问题没有明确说明是否使用方便的库方法，如数组。允许排序（）。实际上，数组。sort（）由于其方便性，我将使用它。如果需要显式编写排序代码，请告诉我，我也可以编写。

另外，在设置比较器时，我使用了lambda语句，这是Java8的一个特性。如果使用Java 7，则使用匿名类。

代码：

    // Test array.
    String[][] test = { { "Bill", "Jones" }, { "Janet", "Kline" }, { "George", "Bailey" },
            { "Ellan", "Sanches" }, { "Tom", "Nguyen" }, { "William", "Walters" }, { "Author", "James" },
            { "Henry", "Daniels" }, { "Mike", "Franklin" }, { "Julie", "Andrews" } };

    // Print unsorted array.
    System.out.println("Unsorted array:");
    for (String[] strArr : test)
    {
        System.out.println(strArr[0] + " " + strArr[1]);
    }

    Scanner input = new Scanner(System.in);
    Comparator<String[]> c;

    // Loop until correct input.
    while (true)
    {
        System.out.println("Sort by first name or last name?");
        System.out.println("Type f for first name, or l for last name.");
        String in = input.nextLine();
        if (in.equals("f"))
        {
            // Set comparator to compare by first name then last name.
            c = (a1, a2) ->
            {
                int result = a1[0].compareTo(a2[0]);
                if (result == 0)
                {
                    result = a1[1].compareTo(a2[1]);
                }
                return result;
            };
            break;
        }
        if (in.equals("l"))
        {
            // Set comparator to compare by last name then first name.
            c = (a1, a2) ->
            {
                int result = a1[1].compareTo(a2[1]);
                if (result == 0)
                {
                    result = a1[0].compareTo(a2[0]);
                }
                return result;
            };
            break;
        }
        System.out.println("Illegal input. Please try again.");
    }

    // Sort.
    Arrays.sort(test, c);

    // Print sorted array.
    System.out.println("Sort complete. Sorted array:");
    for (String[] strArr : test)
    {
        System.out.println(strArr[0] + " " + strArr[1]);
    }