如何对名称的字符串列表使用二级字母排序？

Question

我正在尝试一种方法，当给定一串名字（名字和姓氏）时，名字被 ; 分割，名字和姓氏被 : 分割 ->

"Fred:Corwill;Wilfred:Corwill;Barney:Tornbull;Betty:Tornbull;Bjon:Tornbull;Raphael:Corwill;Alfred:Corwill"

我想要return一个字符串，它把所有的名字都按大写字母排序，并根据姓氏和具有相同姓氏的字母顺序排序，然后再次排序（二次排序）具有相同姓氏的人的名字。（我也故意将所有内容更改为大写）。

和 return 排序名称的字符串，因此对于上面的示例，它应该 return:

"(CORWILL, ALFRED)(CORWILL, FRED)(CORWILL, RAPHAEL)(CORWILL, WILFRED)(TORNBULL, BARNEY)(TORNBULL, BETTY)(TORNBULL, BJON)"

根据姓氏的字母顺序排序，然后在姓氏相同的人之间排序，然后对名字进行次要排序。

我设法进行了主要排序，即按字母顺序对姓氏进行排序，但我不确定如何进行二次排序（在具有相同姓氏的人之间）。我正在考虑拆分成子数组或类似的东西，但我不确定该怎么做。

解决这个问题的方法是什么？

这是我目前所做的（主要排序工作）：

public class Solution {
    public static String meeting(String s) {
        String m = "";
        List<String> name = new ArrayList<String>();
        for (String i : s.toUpperCase().split(";")) {
            String[] n = i.split(":");
            name.add(n[0] + " " + n[1]);
        }
        //main sorting
        java.util.Collections.sort(name);
        //secondary sorting and go through each different last name
        for (String i : name) {
            String[] n = i.split(" ");
            String lastname = n[1];
            // new list for the ppl who share same last name
            List<String> samel = new ArrayList<String>();
            samel.add(n[0]);
            for (String ss : name) {
                String[] nn = ss.split(" ");
                if (nn[1] == lastname) {
                    samel.add(nn[0]);
                }
            }
            //sort the ppl alphabetically with the same last name
            java.util.Collections.sort(samel);
        }
        for (String i : name) {
            String[] n = i.split(" ");
            m += ("(" + n[0] + " , " + n[1] + ")");
        }
        return m;
    }
}

我尝试进行二次排序，但没有成功。

如果我不够清楚，有两种排序，主要是按姓氏字母顺序排序，次要排序只发生在姓氏完全相同的人身上，然后他们的名字会相应地排序字母。所以，如果我们有两个人叫 matt cohn 和 mill cohn，那么他们有相同的姓氏和相同的姓氏首字母，但是 a 在 o 之前，所以输出应该是 (COHN , MATT)(COHN, MILL) 而不是 the反过来。

在下面的解决方案中，我运行它得到了一个错误：

input String:
Alexis:Wahl;John:Bell;Victoria:Schwarz;Abba:Dorny;Grace:Meta;Ann:Arno;Madison:STAN;Alex:Cornwell;Lewis:Kern;Megan:Stan;Alex:Korn

Actual: (ARNO, ANN)(BELL, JOHN)(CORNWELL, ALEX)(DORNY, ABBA)(KERN, LEWIS)(KORN, ALEX)(META, GRACE)(STAN, MADISON)(SCHWARZ, VICTORIA)(STAN, MEGAN)(WAHL, ALEXIS)

Expect: (ARNO, ANN)(BELL, JOHN)(CORNWELL, ALEX)(DORNY, ABBA)(KERN, LEWIS)(KORN, ALEX)(META, GRACE)(SCHWARZ, VICTORIA)(STAN, MADISON)(STAN, MEGAN)(WAHL, ALEXIS)
false

结果是假的

Answer 1

如果您正在使用 Java 流，您可以像这样使用 sorted：

return Arrays.stream(s.split(";"))
        .map(p -> p.split(":"))
        .sorted(Comparator.comparing((String[] p) -> p[1]).thenComparing((String[] p) -> p[0]))
        .map(p -> String.format("(%s, %s)", p[1].toUpperCase(), p[0].toUpperCase()))
        .collect(Collectors.joining());

输出

(CORWILL, ALFRED)(CORWILL, FRED)(CORWILL, RAPHAEL)(CORWILL, WILFRED)(TORNBULL, BARNEY)(TORNBULL, BETTY)(TORNBULL, BJON)

我还建议使用对象而不是字符串来存储您的信息，使用它不是一个好习惯。

Answer 2

一个可能的解决方案如下：

public class ExtractAndSortNames {

    public static String extractAndSort(String s) {
        return Stream.of(s.split(";"))
                .map(String::toUpperCase)
                .map(ExtractAndSortNames::extractPersonFirstNameAndLastName)
                .sorted(Comparator.comparing(FirstNameAndLastName::getLastName).thenComparing(FirstNameAndLastName::getFirstName))
                .map(FirstNameAndLastName::format)
                .collect(Collectors.joining());
    }

    private static FirstNameAndLastName extractPersonFirstNameAndLastName(String personName) {
        var split = personName.split(":");
        var firstName = split[0];
        var lastName = split[1];
        return new FirstNameAndLastName(firstName, lastName);
    }

    private static class FirstNameAndLastName {
        private final String firstName;
        private final String lastName;

        public FirstNameAndLastName(String firstName, String lastName) {
            this.firstName = firstName;
            this.lastName = lastName;
        }
        
        public String getFirstName() {
            return firstName;
        }
        
        public String getLastName() {
            return lastName;
        }
        
        public String format() {
            return String.format("(%s, %s)", this.lastName, this.firstName);
        }
    }
}

没有流的解决方案：

public class ExtractAndSortNames {

    public static String extractAndSort(String s) {
        List<FirstNameAndLastName> toSort = new ArrayList<>();
        for (String s1 : s.split(";")) {
            String toUpperCase = s1.toUpperCase();
            FirstNameAndLastName firstNameAndLastName = extractPersonFirstNameAndLastName(toUpperCase);
            toSort.add(firstNameAndLastName);
        }
        toSort.sort(Comparator.comparing(FirstNameAndLastName::getLastName).thenComparing(FirstNameAndLastName::getFirstName));
        StringBuilder sb = new StringBuilder();
        for (FirstNameAndLastName firstNameAndLastName : toSort) {
            String format = firstNameAndLastName.format();
            sb.append(format);
        }
        return sb.toString();
    }

    private static FirstNameAndLastName extractPersonFirstNameAndLastName(String personName) {
        var split = personName.split(":");
        var firstName = split[0];
        var lastName = split[1];
        return new FirstNameAndLastName(firstName, lastName);
    }

    private static class FirstNameAndLastName {
        private final String firstName;
        private final String lastName;

        public FirstNameAndLastName(String firstName, String lastName) {
            this.firstName = firstName;
            this.lastName = lastName;
        }

        public String getFirstName() {
            return firstName;
        }

        public String getLastName() {
            return lastName;
        }

        public String format() {
            return String.format("(%s, %s)", this.lastName, this.firstName);
        }
    }
}

并测试：

class ExtractAndSortNamesTest {

    @Test
    void test() {
        var input = "Fred:Corwill;Wilfred:Corwill;Barney:Tornbull;Betty:Tornbull;Bjon:Tornbull;Raphael:Corwill;Alfred:Corwill";
        var result = ExtractAndSortNames.extractAndSort(input);

        assertEquals("(CORWILL, ALFRED)(CORWILL, FRED)(CORWILL, RAPHAEL)(CORWILL, WILFRED)(TORNBULL, BARNEY)(TORNBULL, BETTY)(TORNBULL, BJON)", result);
    }

    @Test
    void test2() {
        var input = "Alexis:Wahl;John:Bell;Victoria:Schwarz;Abba:Dorny;Grace:Meta;Ann:Arno;Madison:STAN;Alex:Cornwell;Lewis:Kern;Megan:Stan;Alex:Korn";
        var result = ExtractAndSortNames.extractAndSort(input);

        assertEquals("(ARNO, ANN)(BELL, JOHN)(CORNWELL, ALEX)(DORNY, ABBA)(KERN, LEWIS)(KORN, ALEX)(META, GRACE)(SCHWARZ, VICTORIA)(STAN, MADISON)(STAN, MEGAN)(WAHL, ALEXIS)", result);
    }
}

奖金回合使用 Java 15 预览功能：

public class ExtractAndSortNames {

    public static String extractAndSort(String s) {
        return Stream.of(s.split(";"))
                .map(String::toUpperCase)
                .map(FirstNameAndLastName::from)
                .sorted(Comparator.comparing(FirstNameAndLastName::lastName).thenComparing(FirstNameAndLastName::firstName))
                .map(FirstNameAndLastName::format)
                .collect(Collectors.joining());
    }

    private static record FirstNameAndLastName (String firstName, String lastName) {
        private static FirstNameAndLastName from(String personName) {
            var split = personName.split(":");
            var firstName = split[0];
            var lastName = split[1];

            return new FirstNameAndLastName(firstName, lastName);
        }

        public String format() {
            return "(%s, %s)".formatted(this.lastName, this.firstName);
        }
    }
}

Answer 3

您可以使用比较器链先按一个值排序，然后再按另一个值排序：

String str = "Fred:Corwill;Wilfred:Corwill;Barney:Tornbull;" +
        "Betty:Tornbull;Bjon:Tornbull;Raphael:Corwill;Alfred:Corwill";

List<Map.Entry<String, String>> list = Stream.of(str)
        .map(String::toUpperCase)
        // Stream<String>
        .flatMap(s -> Arrays.stream(s.split(";")))
        // Stream<String[]>
        .map(s -> s.split(":"))
        // Stream<Map.Entry<String,String>>
        .map(arr -> Map.entry(arr[1], arr[0]))
        // sort by last name, then by first name
        .sorted(Map.Entry.<String, String>comparingByKey()
                .thenComparing(Map.Entry::getValue))
        .collect(Collectors.toList());

// output line by line
list.forEach(System.out::println);

输出：

CORWILL=ALFRED
CORWILL=FRED
CORWILL=RAPHAEL
CORWILL=WILFRED
TORNBULL=BARNEY
TORNBULL=BETTY
TORNBULL=BJON

^{另请参阅：How to sort by a field of class with its own comparator?}

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