array.splice在javascript中无法正常工作

I'm writing a simple sudoku solver, which takes an array of numbers 1-9 and sets them to null if they are not possible for that cell. An example is a cell where the answer can only be a 5, so all the numbers are set to null except for five. Then, I have a clean() function which deletes all the values from the array which are null, but that is not working correctly. The original array is this.

我正在编写一个简单的数独求解器，它采用数字1-9的数组，并且如果它们不可能用于该单元格则将它们设置为空。一个例子是一个单元格，其答案只能是5，所以所有数字都设置为null，除了5。然后，我有一个clean（）函数，它删除数组中的所有值为null，但这是无法正常工作。原始数组就是这个。

[null,null,null,null,5,null,null,null,null]

After being cleaned, it returns

清洁后，它返回

[null,null,5,null,null]

The javascript code is here, and the grid is the grid of numbers in the sudoku

javascript代码在这里，网格是数独中的数字网格

function mainmethod(){

        var onepos=oneposs();

    }
    function oneposs(){

        var possibs=new Array(1,2,3,4,5,6,7,8,9);
        for (var ycount=0;ycount<=8;ycount++){
            var value=grid[0][ycount];
            var index=possibs.indexOf(value);
            possibs[index]=null;

        }
    //      for(var xcount=0;xcount<=8;xcount++){
    //      var value=grid[xcount][0];
    //      var index=possibs.indexOf(value);
    //      possibs.splice(index,1);
    //  }

        possibs=clean(possibs);
        alert(JSON.stringify(possibs));
    }
    function clean(array){
        for(var i=0;i<=8;i++){
            if(array[i]===null){
                array.splice(i,1);
            }
        }
        return array;
    }

Essentially, the array.splice is not splicing everything it needs to, and I don't know why

从本质上讲，array.splice并没有拼接所需的一切，我不知道为什么

3 个解决方案

#1

You change the array while you iterate. Try something like that:

您在迭代时更改数组。试试这样的事情：

function clean(array){
    for(var i=0;i<=8;i++){
        if(array[i]===null){
            array.splice(i--,1);
        }
    }
    return array;
}

The -- lower the index because the next item will then be at the same index than the item you are removing.

- 降低索引，因为下一个项目将与您要删除的项目处于相同的索引。

Moreover, objects and arrays passed as argument are passed by reference so you don't need to return anything. You can do clean(possibs);

此外，作为参数传递的对象和数组通过引用传递，因此您不需要返回任何内容。你可以干净（possibs）;

#2

That's because when you "splice" the array , the index change. Maybe you can try this code :

那是因为当你“拼接”数组时，索引会发生变化。也许你可以试试这段代码：

function clean(array){
    var x = [];
    for(var i=0;i<array.length;i++){
        if(array[i]!=null){
            x.push(array[i]);
        }
    }
    return x;
}

#3

try this:

尝试这个：

var array = [null,null,null,null,5,null,null,null,null];
for(var i=0;i<=array.length; ){
    if(array[i] === null){
        array.splice(i,1);
    } else if (array.length < 2) {
        break;
    } else {
        i++;
    }
}

#1