使用平面数组过滤JSON对象

Filter JSON object with flat arrays

本文关键字：JSON 对象 过滤 数组 平面      更新时间：2023-09-26

我有JSON对象与数组对，像这样:

对象{x: Array[36159]， y: Array[36159]， year: Array[36159]}

小样本为例:

{
    "x": [309339618361.619, 102862032084.12102, 72892839276.09761, 46463392384.54194, -39360182208.042145],
    "y": [13950252.45052416, 1158787.402385158, -4368238.261400843, 1339913.7393283844, 2085336.6277048483],
    "year": [1991, 1991, 1992, 1992, 1992]
}

我想按年过滤这个对象。如果JSON数据是数组或键、值对，我可以使用filter:

data.filter(function (x) {
    return x.year == 1991
});

，但作为JSON结构是对平面数组，我不知道如何接近。

期望的结果是:

{
    "x": [309339618361.619, 102862032084.12102],
    "y": [13950252.45052416, 1158787.402385158],
    "year": [1991, 1991]
}

您可以使用带有比较和属性数组的回调，您想要应用过滤器。

var object = {
        "x": [309339618361.619, 102862032084.12102, 72892839276.09761, 46463392384.54194, -39360182208.042145],
        "y": [13950252.45052416, 1158787.402385158, -4368238.261400843, 1339913.7393283844, 2085336.6277048483],
        "year": [1991, 1991, 1992, 1992, 1992]
    },
    result = {};
['x', 'y', 'year'].forEach(function (p) {
    result[p] = object[p].filter(function (a, i) {
        return object.year[i] === 1991;
    });
});
console.log(result);

您可以使用reduce()并按您想要过滤的年份索引添加值。

var obj = {
  "x": [309339618361.619, 102862032084.12102, 72892839276.09761, 46463392384.54194, -39360182208.042145],
  "y": [13950252.45052416, 1158787.402385158, -4368238.261400843, 1339913.7393283844, 2085336.6277048483],
  "year": [1991, 1991, 1992, 1992, 1992]
}
var result = obj.year.reduce(function(r, e, i) {
  if (e == 1991) {
    r.x = (r.x || []).concat(obj.x[i]);
    r.y = (r.y || []).concat(obj.y[i]);
    r.year = (r.year || []).concat(obj.year[i])
  }
  return r;
}, {});
console.log(result)

简单地复制obj并迭代year属性的元素并删除不等于1991的元素。

var obj = {
    x:    [309339618361.619, 102862032084.12102],
    y:    [13950252.45052416, 1158787.402385158],
    year: [1991, 1991]
},
    scan = {};
Object.assign(scan, obj);
for(var i = 0, len = scan.year.length; i < len; i ++) {
    if(scan.year[i] !== 1991) {
        scan.year.splice(i, 1);
    }
}
console.log(scan);
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