17

我正在使用可以具有子类别对象数组的类别对象数组。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）。（参见底部的示例。）我想要做的是向类别对象返回一个“轨迹”，但我遇到了各种各样的困难。

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

我认为我的问题是我无法正确打破由递归引起的嵌套循环。有时我会在我的追踪中获得额外的类别，或者当我认为我已经突破时，一些更深层次的嵌套类别最终会出现在追踪中。

一个结果可能如下所示。显然，它并没有杀死 b4 的循环，我不确定为什么会发现两次结果。

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

如果您还可以向我展示 underscore.js 版本，则可以加分。

JSFiddle 链接在这里...

// 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'));

例如，数组类别对象，具有嵌套的类别对象数组。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:[]
                }
            ]
        }
    ]
}
];
4

2 回答 2

24

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：小提琴

于 2013-04-26T04:21:15.687 回答
0

return stmt 确实有效，但请记住，每次循环展开时都会调用它，而这不是您要查看的内容。例子

// 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.
  }

}
于 2016-06-29T17:50:07.500 回答