Question

如何从深层嵌套的json数组中获取值我需要从json

下面获取所有对（nameValue和value）

  var json = [{
                name: 'Firstgroup',
                elements: [{
                    name: 'Field1',
                    elements: [{
                        name: 'country32',
                        elements: [{
                            nameValue: 'city1',
                            value: 2025
                        }]
                    }]
                },
                    {
                        name: 'Field2',
                        elements: [{
                            name: 'country22',
                            elements: [{
                                nameValue: 'city2',
                                value: 1875
                            }]
                        },
                            {
                                name: 'country12',
                                elements: [{
                                    nameValue: 'city3',
                                    value: 1810
                                }]
                            }]
                    }]
            },
                {
                    name: 'Secondgroup',
                    elements: [{
                        name: 'Field1',
                        elements: [{
                            name: 'country52',
                            elements: [{
                                nameValue: 'city4',
                                value: 1310
                            },
                                {
                                    nameValue: 'city5',
                                    value: 1125
                                }]
                        }]
                    },
                        {
                            name: 'Field3',
                            elements: [{
                                name: 'country42',
                                elements: [{
                                    nameValue: 'city6',
                                    value: 1100
                                }]
                            }]
                        }]
                }];

我设法通过下面这段代码获得第一对

 function getDataProvider(array)
    {
        var dataPoint = [];
        var elements = 'elements';
        var name = 'nameValue';
        var value = 'value';

        var i, j, len;

       for (j = 0; j < array.length; j++) {
           i = array[j];
           if (i[elements]) {
               this.getDataProvider(i[elements]);
            } else {
               dataPoint.push({
                   name: i[name],
                   value: i[value]
               });
            }
        }
       return dataPoint;
    }

我如何从上面的json中得到所有对，因为这个json是动态的，它的深度未知，但它将包含（名称值和值）对

Answer 1

您可以使用迭代和递归方法在数组中获取所需的属性。

function getKeyValue(array) {
    var result = [];
    array.forEach(function iter(o) {
        if (o.elements) {
            o.elements.forEach(iter);
            return;
        }
        result.push({ name: o.nameValue, value: o.value });
    });
    return result;
}

var data = [{ name: 'Firstgroup', elements: [{ name: 'Field1', elements: [{ name: 'country32', elements: [{ nameValue: 'city1', value: 2025 }] }] }, { name: 'Field2', elements: [{ name: 'country22', elements: [{ nameValue: 'city2', value: 1875 }] }, { name: 'country12', elements: [{ nameValue: 'city3', value: 1810 }] }] }] }, { name: 'Secondgroup', elements: [{ name: 'Field1', elements: [{ name: 'country52', elements: [{ nameValue: 'city4', value: 1310 }, { nameValue: 'city5', value: 1125 }] }] }, { name: 'Field3', elements: [{ name: 'country42', elements: [{ nameValue: 'city6', value: 1100 }] }] }] }],
    result = getKeyValue(data);

console.log(result);

.as-console-wrapper { max-height: 100% !important; top: 0; }

为每个递归调用返回一个数组的版本。

function getKeyValue(array) {
    return array.reduce((r, o) => r.concat(
        o.elements
            ? getKeyValue(o.elements)
            : { name: o.nameValue, value: o.value }
    ), []);
}

var data = [{ name: 'Firstgroup', elements: [{ name: 'Field1', elements: [{ name: 'country32', elements: [{ nameValue: 'city1', value: 2025 }] }] }, { name: 'Field2', elements: [{ name: 'country22', elements: [{ nameValue: 'city2', value: 1875 }] }, { name: 'country12', elements: [{ nameValue: 'city3', value: 1810 }] }] }] }, { name: 'Secondgroup', elements: [{ name: 'Field1', elements: [{ name: 'country52', elements: [{ nameValue: 'city4', value: 1310 }, { nameValue: 'city5', value: 1125 }] }] }, { name: 'Field3', elements: [{ name: 'country42', elements: [{ nameValue: 'city6', value: 1100 }] }] }] }],
    result = getKeyValue(data);

console.log(result);

.as-console-wrapper { max-height: 100% !important; top: 0; }

Answer 2

你可以创建一个递归函数，当它有更多元素时调用它自己，并在每次遇到结果时将值添加到它的结果中。

var getNameAndValues = function(arr) {
  var nameValuePairs = [];
  for (var i = 0, len = arr.length; i < len; i++) {
    var item = arr[i];
    if (item.value && item.nameValue) {
      nameValuePairs.push(item);
    }
    if (item.elements) {
      nameValuePairs = nameValuePairs.concat(getNameAndValues(item.elements));
    }
  }
  return nameValuePairs;
};

var json = [{
                name: 'Firstgroup',
                elements: [{
                    name: 'Field1',
                    elements: [{
                        name: 'country32',
                        elements: [{
                            nameValue: 'city1',
                            value: 2025
                        }]
                    }]
                },
                    {
                        name: 'Field2',
                        elements: [{
                            name: 'country22',
                            elements: [{
                                nameValue: 'city2',
                                value: 1875
                            }]
                        },
                            {
                                name: 'country12',
                                elements: [{
                                    nameValue: 'city3',
                                    value: 1810
                                }]
                            }]
                    }]
            },
                {
                    name: 'Secondgroup',
                    elements: [{
                        name: 'Field1',
                        elements: [{
                            name: 'country52',
                            elements: [{
                                nameValue: 'city4',
                                value: 1310
                            },
                                {
                                    nameValue: 'city5',
                                    value: 1125
                                }]
                        }]
                    },
                        {
                            name: 'Field3',
                            elements: [{
                                name: 'country42',
                                elements: [{
                                    nameValue: 'city6',
                                    value: 1100
                                }]
                            }]
                        }]
                }];

var result = getNameAndValues(json);
var asString = "";
for (var i = 0, len = result.length; i < len; i++) {
  var item = result[i];
  asString += item.nameValue + ": " + item.value + "<br/>";
}
document.body.innerHTML = asString;

从javascript

2 个答案: