Question

我正在处理一组类别对象，这些对象可以包含子类别对象数组。棘手的部分是这个嵌套数据的深度是未知的（并且可以改变）。（请参阅底部的示例。）我要做的是返回类别对象的“踪迹”，但我遇到了各种各样的困难。

理想情况下，findCategory('b4')之类的内容会返回：['c1', 'd2', 'd3', 'b4']（参见示例）。

我认为我的问题是我在正确分解由递归引起的嵌套循环方面遇到了麻烦。有时我会在我的踪迹中获得额外的类别，或者当我认为我已经爆发时，一些更深层次的嵌套类别最终会出现在路径中。

一个结果可能如下所示。显然，它并没有在b4处杀死循环，我不确定为什么结果会被发现两次。

b4
FOUND
["c1", "d2", "d3", "b4"]
e2
FOUND
["c1", "d2", "d3", "b4", "e2"]

如果您还可以向我展示一个underscore.js版本，那就获得奖励。

JSFiddle Link这里......

// Start function
function findCategory(categoryName) {
    var trail = [];
    var found = false;

    function recurse(categoryAry) {

        for (var i=0; i < categoryAry.length; i++) {
            console.log(categoryAry[i].category);
            trail.push(categoryAry[i].category);

            // Found the category!
            if ((categoryAry[i].category === categoryName) || found) {
                console.log('FOUND');
                found = true;
                console.log(trail);
                break;

            // Did not match...
            } else {

                // Are there children / sub-categories? YES
                if (categoryAry[i].children.length > 0) {

                    console.log('recurse');
                    recurse(categoryAry[i].children);

                // NO
                } else {
                    trail.pop();
                    if (i === categoryAry.length - 1) {
                        trail.pop();
                    }
                }
            }

        } 
    }

    return recurse(catalog);
}

console.clear();
console.log(findCategory('b4'));

E.g。数组类别对象，具有类别对象的嵌套数组。假设嵌套深度未知。

var catalog = [
{
    category:"a1",
    children:[
        {
            category:"a2",
            children:[]
        },
        {
            category:"b2",
            children:[
                {
                    category:"a3",
                    children:[]
                },
                {
                    category:"b3",
                    children:[]
                }
            ]
        },
        {
            category:"c2",
            children:[]
        }
    ]
},
{
    category:"b1",
    children:[]
},
{
    category:"c1",
    children:[
        {
            category:"d2",
            children:[
                {
                    category:"c3",
                    children:[]
                },
                {
                    category:"d3",
                    children:[
                        {
                            category:"a4",
                            children:[]
                        },
                        {
                            category:"b4",
                            children:[]
                        },
                        {
                            category:"c4",
                            children:[]
                        },
                        {
                            category:"d4",
                            children:[]
                        }
                    ]
                }
            ]
        },
        {
            category:"e2",
            children:[
                {
                    category:"e3",
                    children:[]
                }
            ]
        }
    ]
}
];

Answer 1

尝试

function findCategory(categoryName) {
    var trail = [];
    var found = false;

    function recurse(categoryAry) {

        for (var i = 0; i < categoryAry.length; i++) {
            trail.push(categoryAry[i].category);

            // Found the category!
            if ((categoryAry[i].category === categoryName)) {
                found = true;
                break;

                // Did not match...
            } else {
                // Are there children / sub-categories? YES
                if (categoryAry[i].children.length > 0) {
                    recurse(categoryAry[i].children);
                    if(found){
                        break;
                    }
                }
            }
            trail.pop();
        }
    }

    recurse(catalog);

    return trail
}

演示：Fiddle

Answer 2

返回stmt确实有效，但记住每次循环展开时都会调用它，而不是你正在看的那个。实施例

// global scope
String matchingVariable;

int getMatch(index count, String input, String[] inputs){

  if(isValid(input) || count < inputs.length){
    // your condition is met and break
    // assign your value to global scope variable 
    matchingVariable = input;
  }else if(matchingVariable ==null){
     ++count
     if(count < inputs.length){
       getMatch(count, input+inputs[count], inputs)
     }

    // NOTE RETURN - I WOULDN'T DO THIS
    return input;  

   // doesn't work instead assign the input to global scope variable when a match is found.
  }

}

如何在递归函数中突破循环？

2 个答案: