筛选特定属性并对值求和

Question

我有一个带有多边形的传单地图，您可以单击每个多边形以选择它们，并且有一个信息窗口"L.control"显示所选多边形的值。当您继续单击多边形时，信息窗口会为每个选定的多边形添加值，您将获得所有选定多边形的总值。所有这些都很好，但我需要为特定属性提供更详细的总和，例如下面的区域示例。如果选择了十个多边形，我想区分属性为"南部地区"和"北部地区"的区域的总数以及所有多边形的总数。 这是我正在使用的代码，对不同属性的总数求和没有问题，但是您如何对定义的属性求和？

如何以及在何处添加一种仅对所需属性求和的过滤器解决方案？

$.each(statesData.features, function(index, feature) {
var name = `${feature.properties.ZIPCODE} ${feature.properties.Name}  ( ${feature.properties.average_time} -  ${feature.properties.CITY})`
placenames.push(name);
zipcodes[name] = feature.properties.ZIPCODE;
time = feature.properties.average_time
});
etc.... 
// Now get the totals of selected polygons
var detailshow = function() {
var result = ''
var total = 0
var total1 = 0
var total2 = 0
var total3 = 0
var total4 = 0
for (var i = 0; i < featuresSelected.length; i++) {
var properties = featuresSelected[i].feature.properties
result +=
`
${properties.CITY}<br>
Zipcode: ${properties.ZIPCODE}
<a href="#" onclick=dellayer(${properties.ZIPCODE})>Delete</a>
<hr>`;
total += properties.amount, // sum amount for all regions
total1 += properties.average_time, // in seconds
total2 += properties.distance,
total3 += properties.amount, // amount for Region South only
total4 += properties.amount, // amount for Region North only
// Convert seconds to timeformat
var convertTime = function (input, separator) {
var pad = function(input) {return input < 10 ? "0" + input : input;};
return [
pad(Math.floor(input / 3600)),
pad(Math.floor(input % 3600 / 60)),
pad(Math.floor(input % 60)),
].join(typeof separator !== 'undefined' ?  separator : ':' );
}
var resultTime = convertTime(total1);
}
return {
result: result,
total: total,
resultTime: resultTime,
total2: total2
total3: total3
total4: total4
};
}
detailsselected.update = function(arrayselected) {
var details = detailshow()
this._div.innerHTML =
'<b>Zipcodes</b><br>' + 
'Total time: <b>' + details.resultTime + ' hh:mm:ss</b><br>' +
'Total amount: <b>' + details.total + ' st</b><br>' +
'Region South amount: <b>' + details.total3 + ' st</b><br>' +
'Region North amount: <b>' + details.total4 + ' st</b><br>' +
'Distance: <b>' + details.total2.toFixed(1) + ' km</b><br>';
$('#suma', window.parent.document).val(details.resultTime, details.total, details.total2, details.total3, details.total4);

};
detailsselected.addTo(map);

已选功能：

function checkExistsLayers(feature) {
var result = false
for (var i = 0; i < featuresSelected.length; i++) {
if (featuresSelected[i].ZIPCODE == feature.properties.ZIPCODE) {
result = true;
break;
}
};
return result

}

这是 json 文件结构的一部分：

var statesData = new L.LayerGroup;
var statesData = {"type":"FeatureCollection","features":[{"type":"Feature","properties":{"ZIPCODE":12345,"CITY":"LONDON","REGION":"REGION SOUTH","amount":1088,"average_time":26150,"distance":2.2},"geometry":{"type":"MultiPolygon","coordinates":...

我确实尝试了以下方法，但没有奏效...

function filt_north (feature){
if (feature.properties.REGION === 'REGION NORTH' )
return true;
}
total4 += filt_north.(properties.amount), // amount for Region North only

Answer 1

你写的filt_north函数看起来不错，只需添加一个filt_south过滤器即可获取南部区域并执行以下操作：

let filteredResults = featuresSelected.filter(
result => filt_north(result.feature) || filt_south(result.feature)
);
for (let result of filteredResults) {
var properties = result.feature.properties;
...

Answer 2

尝试了您的解决方案，似乎它破坏了代码并且总数根本没有加起来=停止工作。我这样做了，应该以不同的方式完成吗？ 过滤功能：

function filt_south (feature){
if (feature.properties.REGION === 'REGION SOUTH')
return true;
}
function filt_north (feature){
if (feature.properties.REGION === 'REGION NORTH')
return true;
}

然后改成这个(我一定是在这里做错了什么(：

// Now get the totals of selected polygons
var detailshow = function() {
var result = ''
var total = 0
var total1 = 0
var total2 = 0
var total3 = 0
var total4 = 0
let filteredResults = featuresSelected.filter(
result => filt_south(result.feature) || filt_north(result.feature)
);
for (let result of filteredResults) {
var properties = result.feature.properties;
for (var i = 0; i < featuresSelected.length; i++) { 
var properties = featuresSelected[i].feature.properties
result +=
`
${properties.CITY}<br>
Zipcode: ${properties.ZIPCODE}
<a href="#" onclick=dellayer(${properties.ZIPCODE})>Delete</a>
<hr>`;
total += properties.amount, // sum amount for all regions
total1 += properties.average_time,
total2 += properties.distance,
total3 += filt_south (properties.amount), // amount for Region South only
total4 += filt_north (properties.amount) // amount for Region North only
// Convert seconds to timeformat
var convertTime = function (input, separator) {
var pad = function(input) {return input < 10 ? "0" + input : input;};
return [
pad(Math.floor(input / 3600)),
pad(Math.floor(input % 3600 / 60)),
pad(Math.floor(input % 60)),
].join(typeof separator !== 'undefined' ?  separator : ':' );
}
var resultTime = convertTime(total1);
}
}
return {
result: result,
total: total,
resultTime: resultTime,
total2: total2
total3: total3
total4: total4
};
}
detailsselected.update = function(arrayselected) {
var details = detailshow()
this._div.innerHTML =
'<b>Zipcodes</b><br>' + 
'Total time: <b>' + details.resultTime + ' hh:mm:ss</b><br>' +
'Total amount: <b>' + details.total + ' st</b><br>' +
'Region South amount: <b>' + details.total3 + ' st</b><br>' +
'Region North amount: <b>' + details.total4 + ' st</b><br>' +
'Distance: <b>' + details.total2.toFixed(1) + ' km</b><br>';
$('#suma', window.parent.document).val(details.resultTime, details.total, details.total2, details.total3, details.total4);

};
detailsselected.addTo(map)