javascript - 从重复的 javascript 数组结果集中仅获取一行

Question

我有以下文本文件stops.txt。

stop_id,stop_code,stop_name,stop_lat,stop_lon,zone_id,stop_url,location_type,parent_station,platform_code,wheelchair_boarding
70011,70011,San Francisco Caltrain,37.77639,-122.394992,1,http://www.caltrain.com/stations/sanfranciscostation.html,0,ctsf,NB,1
70012,70012,San Francisco Caltrain,37.776348,-122.394935,1,http://www.caltrain.com/stations/sanfranciscostation.html,0,ctsf,SB,1
70021,70021,22nd St Caltrain,37.757599,-122.39188,1,http://www.caltrain.com/stations/22ndstreetstation.html,0,ct22,NB,2
70022,70022,22nd St Caltrain,37.757583,-122.392404,1,http://www.caltrain.com/stations/22ndstreetstation.html,0,ct22,SB,2

这是我的 JavaScript 函数，用于将 stop_names 索引获取到 datalist:

get('../data/stops.txt').then(function(response) {
      //console.log("Success!", response.split(/(\r\n|\n)/));
      var stop_list = response.split(/(\r\n|\n)/);
      var re = /,/;
      var headers = stop_list.shift().split(re);
      var index = headers.indexOf("stop_name");
      //Removing [index] at return val.split(re)[index]; should return an array of arrays of each split value
      var res = stop_list.map(function(val, key) {
        return val.split(re)[index];
      }).filter(Boolean);

       var str = '';
        var i;
        for (i = 0; i < res.length; i++) {
           str += '<option value="'+res[i]+'" />';
        }
        var s_list=document.getElementById("slist");
        s_list.innerHTML = str;
    }, function(error) {
      console.error("Failed!", error);
    });

这非常完美。但由于第一行与第 2 行具有相同的停靠点名称。

我想要的是如果stop_name和plate_form相同，则只得到一个stop_name的结果集。

Answer 1

您需要做的就是在定义 res 时将过滤器添加到链的末尾以删除重复值。这个问题已经解决了几次:Unique values in an array

它看起来像这样:

var res = stop_list
  .map(function(val, key) {
    return val.split(re)[index];
  })
  .filter(function(value, index, self) { 
    return self.indexOf(value) === index;
  });