如何访问ArrayList中的ArrayList？ Java的

Question

首先让我告诉你我想做什么。 该程序应要求输入密码，然后为密码的每个字符创建数组列表。 然后，这些列表将被添加到整个数组列表。（mylist）问题是我该如何使用字符串值填充ArrayList？ 当所有数组列表都填充后，我希望能够按字母顺序对其进行排序。 代码打击。

// Creating ArrayLists
ArrayList<ArrayList<String>> mylist = new ArrayList<ArrayList<String>>();
List<String> mycode = new ArrayList<String>();    
char[] test;
String mypassword;

System.out.println("Pleaseinput your passphrase");
        // Getting user input (Password)
        Scanner in = new Scanner(System.in);
        mypassword = in.nextLine();
        // Storing password in character array
        test= mypassword.toCharArray();

    // Beginning for loop to create array lists for each character
    // in the password
    for (int i = 0; i < mypassword.length(); i++) { 
            mycode = new ArrayList<String>();
            // Here I'm trying to give the created Arraylist (mycode)
            // a name or value of the character the for loop is at so I                  can order it alphabetically later.
            mycode.equals(test[i]);
            // Adds the array list.
            mylist.add((ArrayList<String>) mycode);
        }

预先感谢您对我的问题的任何建议。

Answer 1

从注释中假定，您只想将String转换为List<String> ，其中每个字符都是String ，但要使每个字符作为列表中的第一个元素，而让“ hello”作为列表中的第二个元素q ...

public static void main(String[] args) {
    // Creating ArrayLists
    List<List<String>> mylist = new ArrayList<>();
    String mypassword;

    System.out.println("Pleaseinput your passphrase:");
    // Getting user input (Password)
    Scanner in = new Scanner(System.in);
    mypassword = in.nextLine();

    // Beginning for loop to create array lists for each character
    // in the password      
    for (int i = 0; i < mypassword.length(); i++) { 
        List<String> firstCharAndMore = new ArrayList<>();
        char c = mypassword.charAt(i);
        firstCharAndMore.add(String.valueOf(c));
        if ('q' == c) {
            firstCharAndMore.add("hello");
        }
        mylist.add(firstCharAndMore);
    }
    System.out.println(mylist.toString());
}

输入qwertyqwerty输出： [[q, hello], [w], [e], [r], [t], [y], [q, hello], [w], [e], [r], [t], [y]]