如何根据分隔符将数组列表分割成两个数组列表？

huangapple
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英文:

How do I split an array list into two array lists based on a delimiter?

问题

假设我有一个数组列表的数组列表：

  1. A = [2, 5, 6], [1, 6, 1], [], [7, 7], [4, 2], [9, 3]]

我想在其中数组列表的元素大小为0的索引处将它们分割，使其看起来像这样：

  1. x = [[2, 5, 6], [1, 6, 1]]
  2. y = [[7, 7], [4, 2], [9, 3]]

但无论我运行循环如何，结果都是这样的：

  1. for(int i = 0; i < A.size(); i++) {
  2. 	ArrayList temp= A.get(i);
  3. 	int size = temp.size();
  4. 	if(size != 0) {
  5. 	   x.add(temp);
  6. 	}
  7. 	   y.add(temp);
  8. 	}
  1. x = [[2, 5, 6], [1, 6, 1], [7, 7], [4, 2], [9, 3]]
  2. y = [[2, 5, 6], [1, 6, 1], [], [7, 7], [4, 2], [9, 3]]

有人可以帮我解决这个问题吗？

英文:

Suppose that I have an Array list of Array lists:

  1. A = [2, 5, 6], [1, 6, 1], [], [7, 7], [4, 2], [9, 3]]

and I want to split them at the index where the element of the array list has the size of 0 so that it will look like this

  1. x = [[2, 5, 6], [1, 6, 1]]
  2. y = [[7, 7], [4, 2], [9, 3]]

but whenever I run my loop it comes out like this:

  1. for(int i = 0; i < A.size(); i++) {
  2. 	ArrayList temp= A.get(i);
  3. 	int size = temp.size();
  4. 	if(size != 0) {
  5. 	   x.add(temp);
  6. 	}
  7. 	   y.add(temp);
  8. 	}
  1. x = [[2, 5, 6], [1, 6, 1], [7, 7], [4, 2], [9, 3]]
  2. y = [[2, 5, 6], [1, 6, 1], [], [7, 7], [4, 2], [9, 3]]

Can anyone please help me figure this out?

答案1

得分: 1

你的逻辑有问题。目前，你避免将空列表写入x；除此之外，你总是同时向x和y写入数据。

你可以使用一个布尔值来指示数据必须写入哪个列表。一旦你看到一个大小为0的列表，就切换这个标志。

  1. boolean writeToX = true;
  3. for (int i = 0; i < A.size(); i++) {
  4.     ArrayList temp = A.get(i);
  5.     int size = temp.size();
  6.     if (size == 0) {
  7.         writeToX = false;
  8.         continue;
  9.     }
  10.     if (writeToX) {
  11.         x.add(temp);
  12.     } else {
  13.         y.add(temp);
  14.     }
  15. }

附注：避免使用原始类型。

https://stackoverflow.com/questions/2770321/what-is-a-raw-type-and-why-shouldnt-we-use-it

英文:

You logic is off. Currently you are avoiding writing the empty list into x; other than that you always write to both x and y.

You can have a boolean to say which list the data must be written to. Once you see a list with size 0, switch the flag.

  1. boolean writeToX = true;
  3. for(int i = 0; i &lt; A.size(); i++) {
  4.     ArrayList temp= A.get(i);
  5.     int size = temp.size();
  6.     if(size == 0) {
  7.        writeToX = false;
  8.        continue;
  9.     }
  10.     if (writeToX) {
  11.         x.add(temp);
  12.     } else {
  13.         y.add(temp);
  14.     }
  15.       
  16. }

Sidenote: Avoid using raw types.

https://stackoverflow.com/questions/2770321/what-is-a-raw-type-and-why-shouldnt-we-use-it

答案2

得分: 1

你需要像这样跟踪目标数组：

  1. boolean addToX = true;
  3. for(ArrayList temp : A) {
  4.   if(temp.isEmpty()) {
  5.     addToX = false;  
  6.   } else if(addToX) {
  7.     x.add(temp);
  8.   } else {
  9.     y.add(temp);
  10.   }
  11. }
英文:

You need to keep track of the destination array like this:

  1. boolean addToX = true;
  3. for(ArrayList temp : A) {
  4.   if(temp.isEmpty()) {
  5.     addToX = false;  
  6.   } else if(addToX) {
  7.     x.add(temp);
  8.   } else {
  9.     y.add(temp);
  10.   }
  11. }

答案3

得分: 0

尝试这个，在代码中添加一个布尔标志来标识：

  1. boolean flag = false;
  2. for (int i = 0; i < A.size(); i++) {
  3.     ArrayList temp = A.get(i);
  4.     int size = temp.size();
  5.     if (size != 0 && flag == false) {
  6.         x.add(temp);
  7.     } else if (size == 0) {
  8.         flag = true;
  9.     } else if (size != 0 && flag == true) {
  10.         y.add(temp);
  11.     }
  12. }
英文:

Try this, add a boolen flag to identify :-

  1. 	boolean flag=false;
  2. 	for(int i = 0; i &lt; A.size(); i++) {
  3. 	    ArrayList temp= A.get(i);
  4. 	    int size = temp.size();
  5. 	    if(size != 0 &amp;&amp; flag==false) {
  6. 	       x.add(temp);
  7. 	    }else if(size==0) {
  8. 	       flag=true;
  9. 	    }else if(size != 0 &amp;&amp; flag==true){
  10. 	    	y.add(temp);
  11. 	    }

答案4

得分: 0

这是正常的，因为你只是没有将空元素放入 x，但你将所有其他元素都放入了 x 和 y。你可以有一个名为 isNullArrayCome 的布尔参数，在每次迭代时检查它。这里是代码示例：

  1. boolean isNullArrayCome = false;
  2. for (int i = 0; i < A.size(); i++) {
  3.     ArrayList temp = A.get(i);
  4.     int size = temp.size();
  5.     if (size == 0) {
  6.         isNullArrayCome = true;
  7.     }
  8.     if (!isNullArrayCome) {
  9.         x.add(temp);
  10.     } else {
  11.         y.add(temp);
  12.     }
  13. }
英文:

it is normal because you are just not putting the empty element to x but you are putting all other elements to x and y. You can have a boolean parameter, such as isNullArrayCome and check it on every iteration. Here it is

  1. boolean isNullArrayCome = false;
  2. for(int i = 0; i &lt; A.size(); i++) {
  3.     ArrayList temp= A.get(i);
  4.     int size = temp.size();
  5.     if(size == 0 ) {
  6.       isNullArrayCome = true;
  7.      }
  8.      if(!isNullArrayCome){
  9.        x.add(temp);
  10.      } else {
  11.        y.add(temp);
  12.      }
  13. }

huangapple
  • 本文由 发表于 2020年10月23日 16:07:44
  • 转载请务必保留本文链接：https://go.coder-hub.com/64496250.html
  • arraylist
  • java
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