在Java中排序一个多维字符数组

Question

我有一个多维字符串数组处理[100][2]，如下所示:

Y B

C D

B

B C

F E

E Y

F D

X Y

E G

我想按第一列字母排序，使最终结果看起来如下:

B

B C

C D

E Y

E G

F E

F D

Y B

X Y我试过使用下面的代码，但这并不奏效:

Arrays.sort(process, new Comparator<String[]>() {
        @Override
        public int compare(final String[] entry1, final String[] entry2) {
                final String time1 = entry1[0];
                final String time2 = entry2[0];
                return time1.compareTo(time2);
        }
});

我得到的输出是: B

B C

C D

E Y

F E

Y B

E G

F D

X Y

Answer 1

下面的单元测试演示了一个工作的Comparator实现。测试也打印出结果。

import java.util.Arrays;
import java.util.Comparator;
import junit.framework.TestCase;
public class ArrayTest extends TestCase {
    public class Sorter implements Comparator {
        public int compare(Object o1, Object o2){
            String[] arrayOne = (String[])o1;
            String[] arrayTwo = (String[])o2;
            return arrayOne[0].compareTo(arrayTwo[0]);
        }
    }
    public void testSort() {
        String[][] testData = {
                {"Y", "B"},
                {"C", "D"},
                {"A", "B"},
                {"B", "C"},
                {"F", "E"},
                {"E", "Y"},
        };
        Arrays.sort(testData, new Sorter());
        String[][] expectedOutput = {
                {"A", "B"},
                {"B", "C"},
                {"C", "D"},
                {"E", "Y"},
                {"F", "E"},
                {"Y", "B"},
        };
        for(int i = 0; i < testData.length; ++i) {            
            System.out.println(testData[i][0] + " " + testData[i][1]);
            assertEquals(expectedOutput[i][0], testData[i][0]);
            assertEquals(expectedOutput[i][1], testData[i][1]);            
        }
    }
}

Answer 2

这段代码(相同的比较器)按预期工作:

    String[][] arr = {{"B","L"},{"C","M"},{"Z","N"}};
    Arrays.sort(arr, new Comparator<String[]>() {
        @Override
        public int compare(final String[] entry1, final String[] entry2) {
            final String time1 = entry1[0];
            final String time2 = entry2[0];
            return time1.compareTo(time2);
        }
    });

你的问题一定在别处

Answer 3

最好将这两个字符放在每行的同一元素中。然后，当需要分隔字符时，使用

String firstCharacter = myString.charAt(0);
String secondCharacter = myString.charAt(1);

你可以对你的一维数组进行排序