java - 如何对多维Arraylist进行排序》ArrayList<string[]>“在Java中？</string[]>

问题描述

我编写了一个代码，ArrayList<String[]>通过 each 的第一个元素对多维 ArrayList 进行排序String[]，2dArray 如下所示：

{
 ["Mark", "mark@mail.com"],
 ["Angela", "zzAngela@gmail.com"],
 ["Harry", "abc_harry@hotmail.com"],
 ["Donald","donny@aol.com"]
}

但是当我运行代码时，数组没有排序，有人可以解释我的代码有什么问题吗？已经谢谢你了！

ArrayList<String[]> sorter = new ArrayList<String[]>();
String file_name = "db_email.csv";

// READING FROM CSV FILE & STORING DATA INTO 2dARRAY
try{

    BufferedReader reader = new BufferedReader(new FileReader (file_name));

    String line = reader.readLine(); // read the rest
    String[] row;

    while(line != null){

    String[] result = line.split(","); 
    sorter.add(new String[]{result[0], result[1]});
    line = reader.readLine();
    }

    reader.close(); 
} catch (IOException e){
    System.out.println(e);
}

// MY SORTING ALGORITHM
Collections.sort(sorter, new Comparator<String[]>() { 

    @Override
    public int compare(String[] o1, String[] o2) {
        return o1[0].compareTo(o2[0]);
    }               
});

// EXPECTED RESULT (sorting 2dArray by 1st column):
{
 ["Angela", "zzAngela@gmail.com"],
 ["Donald","donny@aol.com"],
 ["Harry", "abc_harry@hotmail.com"],
 ["Mark", "mark@mail.com"]
}

// ACTUAL RESULT (the array doesn't get sorted):
{
 ["Mark", "mark@mail.com"],
 ["Angela", "zzAngela@gmail.com"],
 ["Harry", "abc_harry@hotmail.com"],
 ["Donald","donny@aol.com"]
}

标签： javasortingarraylistmultidimensional-array

java - 如何对多维Arraylist进行排序》ArrayList“在Java中？

问题描述

解决方案

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