使用Java将基于值的值列表拆分为列表

Question

考虑一个长值列表[1,2,3,4,2,3,6,3,7,3]。我需要实现 java 程序来根据值拆分列表。假设value = 3。每当我找到value = 3。我需要以[[1,2] ,[3],[4,2],[3],[6],[3],[7],[3]] 的方式拆分列表。

我写了下面的代码来实现问题陈述：

    public class Solution {
    public static void main(String args[]) {
      List<Integer> list = new ArrayList<Integer>();
      list.add(1);
      list.add(2);
      list.add(3);
      list.add(4);
      list.add(2);
      list.add(3);
      list.add(6);
      list.add(3);
      list.add(7);
      System.out.println(list);

      int val = 3;
      List<List<Integer>> finalList = new ArrayList<>();
      List<Integer> tempList = new ArrayList<>();

      for (int i : list) {
          if (i != val) {
              tempList.add(i);
          } else {
              finalList.add(new ArrayList<>(tempList));
              finalList.add(Arrays.asList(i));
              tempList.clear();
          }
      }

        System.out.println(finalList);
    }
}

输出： [[1, 2], [3], [4, 2], [3], [6], [3]]

预期输出： [[1,2] ,[3],[4,2],[3],[6],[3],[7]]

最后一个数字 [7] 未添加到 finalList。任何建议！

Answer 1

问题是您将整个起始列表添加到数组中，

相反，您需要记住其他数组，以便在遇到 3 时可以推动这个数组。

List<Integer> list_i_want_to_push = new ArrayList<>();
for (int i =0; i < list.size(); i++){
              list_i_want_to_push.add(list.get(i));

              if(val == list.get(i)){
                  list_i_want_to_push.remove(i);
                  finalList.add(list_i_want_to_push);
                  finalList.add(Arrays.asList(val));
                  list_i_want_to_push = []; //empty your array
              }

             }
             System.out.println(finalList);

Answer 2

我相信这可以满足您的要求，但我必须做出一些假设。

• 如果出现相邻的拆分编号，只需将每个拆分编号放入自己的列表中并添加到最终列表中。
• 假设列表可以以一个或多个拆分数字开始和/或结束。

import java.util.ArrayList;
import java.util.List;

public class SplitListOnValue {
    public static void main(String args[]) {
        List<Integer> list = new ArrayList<>(List.of(3,3,2,3,4,2,3,3,3,6,6,6,3,7,3,3));
        System.out.println(list);

        int splitVal = 3;
        List<Integer> temp = new ArrayList<>();
        List<List<Integer>> finalList = new ArrayList<>();

        for (int i = 0; i < list.size(); i++) {
            int item = list.get(i);
            if (item == splitVal) {
                // add both list and singleton list if temp not empty
                // other wise just add singletone list
                if (!temp.isEmpty()) {
                    finalList.add(new ArrayList<>(temp));
                }
                finalList.add(new ArrayList<>(List.of(splitVal)));
                // clear temp list and restart process
                temp.clear();
                continue;
            } 
            // still accumulating
            temp.add(item);
        }
        System.out.println(finalList);
    }
}

打印

[[3], [3], [2], [3], [4, 2], [3], [3], [3], [6, 6, 6], [3], [7], [3], [3]]

Answer 3

试试这样：

public static void main(String[] args) {
    // The number you want to split by
    int delimiter = 3;
    List<Integer> input = Arrays.asList(5, 3, 10, 4, 3, 5, 6, 3, 4);

    List<List<Integer>> result = new ArrayList<>();
    result.add(new ArrayList<>()); // Add a list so that we have something to work with

    for (int i = 0; i < input.size(); i++) {
        // Get the next value in the list
        int val = input.get(i);

        // If the current value equals the one we want to split by...
        if (val == delimiter) {
            //... add a new list containing only the delimiter...
            result.add(Arrays.asList(delimiter));

            //... and add a new list so the other values will be added correctly
            result.add(new ArrayList<>());
        } else // if this is just a random number, add it to the last list
            result.get(result.size() - 1).add(val);
    }

    // If the last number in your input is equal to the delimiter, there will be an empty
    // list at the end, which can be prevented this way
    if (result.get(result.size() - 1).size() == 0)
        result.remove(result.size() - 1);

}