开发者问题收集

多维数组关联

2020-11-05
59
javascript arrays multidimensional-array

我有两个数组，routesFeatures 和 stopsFeatures，它们分别包含车辆路线的属性和每个站点的属性。它们通过其名称属性相互关联，这意味着如果 stopsFeatures 中任何条目的 RouteName 属性与 routesFeatures 中任何条目的 Name 属性匹配，则意味着停靠点属于该路线。 现在，从代码角度来看，我正尝试进行这种匹配，并将它们放在一个二维数组中，其中每个索引都是一条路线，并且该索引内有相应的站点。

这是 routesFeatures： 

[{
    ObjectId: 1,
    Name: "Rota 1"
  },
  {
    ObjectId: 2,
    Name: "Rota 2"
  },
  ...
]

这是 stopFeatures： 

[{
    ObjectId: 1,
    Name: "Carga 0",
    RouteName: "Rota 2"
  },
  {
    ObjectId: 2,
    Name: "Descarga 0",
    RouteName: "Rota 2"
  },
  ...,
  {
    ObjectId: 11,
    Name: "Carga 5",
    RouteName: "Rota 4"
  },
  ...
]

这是我的功能： 

function drawRoutesOptimized(routesFeatures, stopsFeatures){
    var stopsRoutes = [[]];
    for(var i=0; i<routesFeatures.length; i++){
        // draw some stuff on screen
        var count = 0;
        for(var j=0; j<stopsFeatures.length; j++){
            if(stopsFeatures[j].attributes.RouteName == routesFeatures[i].attributes.Name){
                stopsRoutes[i][count] = stopsFeatures[j].attributes.Name;
                count++;
            }
        }
    }
}

这是 endsRoutes 的 console.log，它按预期工作，但只有当 i 为 0 时才会崩溃： 

[0]
    [0] "Carga 2"
    [1] "Descarga 2"
    [2] "Carga 6"
    [3] "Descarga 6"
    [4] "Carga 7"
    [5] "Descarga 7"

在我看来，这应该可以工作，但我得到了： 未捕获（在承诺中）TypeError：无法设置未定义的属性“0” 当 i 变为值 1 时

2个回答

从逻辑上讲，这非常简单。

  1. 循环遍历路线
  2. 每个路线，循环遍历站点
  3. 添加 RouteName 与路线匹配的站点

这不是最优化的解决方案，但它有效。请记住，我使用 reduce 将每条路线初始化为数组。 

const routesFeatures = [{
    ObjectId: 1,
    Name: "Rota 1"
  },
  {
    ObjectId: 2,
    Name: "Rota 2"
  },
];
const stopFeatures = [{
    ObjectId: 1,
    Name: "Carga 0",
    RouteName: "Rota 2"
  },
  {
    ObjectId: 2,
    Name: "Descarga 0",
    RouteName: "Rota 2"
  },
  {
    ObjectId: 11,
    Name: "Carga 5",
    RouteName: "Rota 4"
  },
];
const result = routesFeatures.reduce((acc, routeFeature) => {
  acc.push(stopFeatures.reduce((_acc, stopFeature) => {
    if (stopFeature.RouteName === routeFeature.Name) {
      _acc.push(stopFeature.RouteName)
    }
    return _acc;
  }, []))
  return acc
}, []);
console.log(result);

使用标准 for 循环 

const routesFeatures = [{
    ObjectId: 1,
    Name: "Rota 1"
  },
  {
    ObjectId: 2,
    Name: "Rota 2"
  },
];
const stopsFeatures = [{
    ObjectId: 1,
    Name: "Carga 0",
    RouteName: "Rota 2"
  },
  {
    ObjectId: 2,
    Name: "Descarga 0",
    RouteName: "Rota 2"
  },
  {
    ObjectId: 11,
    Name: "Carga 5",
    RouteName: "Rota 4"
  },
];

function drawRoutesOptimized(routesFeatures, stopsFeatures) {
  const routeStops = [];
  for (let i = 0; i < routesFeatures.length; i++) {
    routeStops.push([]);
    const routeArray = routeStops[i];
    const route = routesFeatures[i];
    for (let j = 0; j < stopsFeatures.length; j++) {
      const stop = stopsFeatures[j];
      if (stop.RouteName === route.Name) {
        routeArray.push(stop.RouteName)
      }
    }
  }
  return routeStops
}
const result = drawRoutesOptimized(routesFeatures, stopsFeatures);
console.log(result);
Dane Brouwer
2020-11-05

不太确定您实际上想要什么，我删除了属性参数以使其在代码片段中起作用。您忘记声明子数组，因此当路由无法将数据推送到数组中时。 

let routesFeatures = [{
    ObjectId: 1,
    Name: "Rota 1"
  },
  {
    ObjectId: 2,
    Name: "Rota 2"
  }
]


let stopsFeatures = [{
    ObjectId: 1,
    Name: "Carga 0",
    RouteName: "Rota 2"
  },
  {
    ObjectId: 2,
    Name: "Descarga 0",
    RouteName: "Rota 2"
  }
]

function drawRoutesOptimized(routesFeatures, stopsFeatures){
    var stopsRoutes = [];
    for(var i=0; i<routesFeatures.length; i++){
        // draw some stuff on screen
        var count = 0;
        stopsRoutes[i] = [];
        for(var j=0; j<stopsFeatures.length; j++){
            if(stopsFeatures[j].RouteName == routesFeatures[i].Name){
                stopsRoutes[i][count] = stopsFeatures[j].Name;
                count++;
            }
        }
    }
    console.log(stopsRoutes)
}

drawRoutesOptimized(routesFeatures, stopsFeatures)
syarul
2020-11-05