Jinja2 for循环在列表不工作，但访问单个元素的工作 [英] Jinja2 for loop in javascript on a list not working but accessing individual elements works

问题描述

我正在打造一个烧瓶+ jinja2网站，其中包括在地图上绘制一些存储的标记。

Python代码

  resultroute ['checkpointlist'] = CheckPoint。 query.filter_by（route_id = route.code）
 return render_template（'routes / edit.html'，route = resultroute）
  

Javascript中的edit.html

  function addExistingMarkers（）{
 //单独访问元素
 var name0 ='{{route.checkpointlist [0] .name}}'; 
 var lat0 = {{route.checkpointlist [0] .latitude}}; 
 var long0 = {{route.checkpointlist [0] .longitude}}; 
 var marker = new google.maps.Marker（{
 position：new google.maps.LatLng（{{route.checkpointlist [0] .latitude}}，{{route.checkpointlist [0]。经度}}），
 map：map，
 title：'{{route.checkpointlist [0] .name}}'
}）; 
 
 //尝试迭代列表
 {％for route.checkpointlist％中的检查点} 
 var lat = checkpoint.latitude; 
 var long = checkpoint.longitude; 
 var cpname = checkpoint.name; 
 var location = new google.maps.LatLng（lat，long）; 
 
 var marker = new google.maps.Marker（{
 map：map，
 draggable：true，
 title：cpname，
 animation：google .maps.Animation.DROP，
 position：location，
}）; 
 {％end for％} 
} 
  

这是来自[0]元素的单独访问。但不知何故for循环不工作。

解决方案

  {％for checkpoint in route.checkpointlist％} 
 var lat = {{checkpoint.latitude}}; 
 var long = {{checkpoint.longitude}}; 
 var cpname = {{checkpoint.name}}; 
 var location = new google.maps.LatLng（lat，long）; 
 
 var marker = new google.maps.Marker（{
 map：map，
 draggable：true，
 title：cpname，
 animation：google .maps.Animation.DROP，
 position：location，
}）; 
 {％end for％} 
  

在引用变量时需要包含双括号Jinja模板。

I am working on a flask + jinja2 website which involves plotting some stored markers on a map.

Python code

resultroute['checkpointlist'] = CheckPoint.query.filter_by(route_id=route.code)
return render_template('routes/edit.html',route=resultroute)

Javascript in edit.html

    function addExistingMarkers() {
        //Individual access to elements
        var name0 = '{{route.checkpointlist[0].name}}';
        var lat0 = {{route.checkpointlist[0].latitude}};
        var long0 = {{route.checkpointlist[0].longitude}};
        var marker = new google.maps.Marker({
          position: new google.maps.LatLng({{ route.checkpointlist[0].latitude }}, {{ route.checkpointlist[0].longitude }}),
          map: map,
          title: '{{ route.checkpointlist[0].name }}'
        });

        //Trying to iterate over the list
        {% for checkpoint in route.checkpointlist %}
            var lat = checkpoint.latitude;
            var long = checkpoint.longitude;
            var cpname = checkpoint.name;
            var location = new google.maps.LatLng(lat, long);

            var marker = new google.maps.Marker({
                  map: map,
                  draggable:true,
                  title:cpname,
                  animation: google.maps.Animation.DROP,
                  position: location,
            });
         {% end for %}
    }

Only one marker is getting placed which is from the individual access of [0] element. But somehow the for loop is not working.

解决方案

{% for checkpoint in route.checkpointlist %}
  var lat = {{checkpoint.latitude}};
  var long = {{checkpoint.longitude}};
  var cpname = {{checkpoint.name}};
  var location = new google.maps.LatLng(lat, long);

  var marker = new google.maps.Marker({
    map: map,
    draggable: true,
    title: cpname,
    animation: google.maps.Animation.DROP,
    position: location,
  });
 {% end for %}

You need to include the double braces when referencing variable in a Jinja template.

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