我有以下JSON对象。我想浏览一下，如果元素具有匹配的坐标，则删除副本并保留原始副本。我尝试使用.filter剥离副本，但无法正常工作。剥离副本的最佳方法是什么？
business1 {
"type": "FeatureCollection",
"features": [
{
"type": "Feature",
"geometry": {
"type": "Point",
"coordinates": [
12.564111,
55.675659
]
},
"place_name": "Axeltorv 3, 1609 København, Denmark",
"properties": {
"title": "Comparison of Alternative Meat Inspection Regimes for Pigs From Non-Controlled Housing ? Considering the Cost of Error",
"countries": "Denmark",
"authorTitle": "Lis Alban",
"businessName": "Danish Agriculture and Food Council"
}
},
{
"type": "Feature",
"geometry": {
"type": "Point",
"coordinates": [
12.564111,
55.675659
]
},
"place_name": "Axeltorv 3, 1609 København, Denmark",
"properties": {
"title": "Comparison of Alternative Meat Inspection Regimes for Pigs From Non-Controlled Housing ? Considering the Cost of Error",
"countries": "Denmark",
"authorTitle": "Lisbeth Harm Nielsen",
"businessName": "Danish Agriculture and Food Council"
}
},
{
"type": "Feature",
"geometry": {
"type": "Point",
"coordinates": [
-1.26288597488275,
51.7576388596821
]
},
"place_name": "OX1 2JD, Oxford, Oxfordshire, England, United Kingdom",
"properties": {
"title": "ENSO Drives interannual variation of forest woody growth across the tropics",
"countries": "United Kingdom",
"authorTitle": "C?cile A J Girardin",
"businessName": "University of Oxford"
}
},
{
"type": "Feature",
"geometry": {
"type": "Point",
"coordinates": [
-1.26288597488275,
51.7576388596821
]
},
"place_name": "OX1 2JD, Oxford, Oxfordshire, England, United Kingdom",
"properties": {
"title": "ENSO Drives interannual variation of forest woody growth across the tropics",
"countries": "United Kingdom",
"authorTitle": "Cecilia A L Dahlsj?",
"businessName": "University of Oxford"
}
},
{
"type": "Feature",
"geometry": {
"type": "Point",
"coordinates": [
-111.65511,
35.19363
]
},
"place_name": "1899 PO Box, Flagstaff, Arizona 86011, United States",
"properties": {
"title": "ENSO Drives interannual variation of forest woody growth across the tropics",
"countries": "United States",
"authorTitle": "Christopher E Doughty",
"businessName": "Northern Arizona University"
}
},
{
"type": "Feature",
"geometry": {
"type": "Point",
"coordinates": [
-1.26288597488275,
51.7576388596821
]
},
"place_name": "OX1 2JD, Oxford, Oxfordshire, England, United Kingdom",
"properties": {
"title": "ENSO Drives interannual variation of forest woody growth across the tropics",
"countries": "United Kingdom",
"authorTitle": "Erika Berenguer",
"businessName": "University of Oxford"
}
}
],
}
只有原始版本而不是混合版本的副本会成为跟随者。
business1 {
"type": "FeatureCollection",
"features": [
{
"type": "Feature",
"geometry": {
"type": "Point",
"coordinates": [
12.564111,
55.675659
]
},
"place_name": "Axeltorv 3, 1609 København, Denmark",
"properties": {
"title": "Comparison of Alternative Meat Inspection Regimes for Pigs From Non-Controlled Housing ? Considering the Cost of Error",
"countries": "Denmark",
"authorTitle": "Lis Alban",
"businessName": "Danish Agriculture and Food Council"
}
},
{
"type": "Feature",
"geometry": {
"type": "Point",
"coordinates": [
-1.26288597488275,
51.7576388596821
]
},
"place_name": "OX1 2JD, Oxford, Oxfordshire, England, United Kingdom",
"properties": {
"title": "ENSO Drives interannual variation of forest woody growth across the tropics",
"countries": "United Kingdom",
"authorTitle": "Cecilia A L Dahlsj?",
"businessName": "University of Oxford"
}
},
{
"type": "Feature",
"geometry": {
"type": "Point",
"coordinates": [
-111.65511,
35.19363
]
},
"place_name": "1899 PO Box, Flagstaff, Arizona 86011, United States",
"properties": {
"title": "ENSO Drives interannual variation of forest woody growth across the tropics",
"countries": "United States",
"authorTitle": "Christopher E Doughty",
"businessName": "Northern Arizona University"
}
}
],
}
尝试使用set，它只是返回传递给它的确切对象
uniqueArray = [...new Set(business1.features)]
答案 0 :(得分：1)
您可以使用Array.prototype.filter进行此操作，方法是分解为坐标并检查字符串数组的局部作用域Set。
business1.features.filter(({geometry:{ coordinates }}) =>
!b.has(s(coordinates)) && (b.add(s(coordinates)), true),
b = new Set(), s = JSON.stringify)
// Get the features array
business1.features
// call filter on the array
.filter(
// destructure each feature down to "coordinates"
({geometry:{ coordinates }}) =>
/* check if the local set object contains stringified coordinates
if it does not -
- we add it to the set and respond true
- it is added to the filtered array
if it does -
- we respond false
- it is not added to the filtered array.
*/
!b.has(s(coordinates)) && (b.add(s(coordinates)), true),
// declare our local variables for our Set and stringify:
b = new Set(), s = JSON.stringify)
let business1={type:"FeatureCollection",features:[{type:"Feature",geometry:{type:"Point",coordinates:[12.564111,55.675659]},place_name:"Axeltorv 3, 1609 København, Denmark",properties:{title:"Comparison of Alternative Meat Inspection Regimes for Pigs From Non-Controlled Housing ? Considering the Cost of Error",countries:"Denmark",authorTitle:"Lis Alban",businessName:"Danish Agriculture and Food Council"}},{type:"Feature",geometry:{type:"Point",coordinates:[12.564111,55.675659]},place_name:"Axeltorv 3, 1609 København, Denmark",properties:{title:"Comparison of Alternative Meat Inspection Regimes for Pigs From Non-Controlled Housing ? Considering the Cost of Error",countries:"Denmark",authorTitle:"Lisbeth Harm Nielsen",businessName:"Danish Agriculture and Food Council"}},{type:"Feature",geometry:{type:"Point",coordinates:[-1.26288597488275,51.7576388596821]},place_name:"OX1 2JD, Oxford, Oxfordshire, England, United Kingdom",properties:{title:"ENSO Drives interannual variation of forest woody growth across the tropics",countries:"United Kingdom",authorTitle:"C?cile A J Girardin",businessName:"University of Oxford"}},{type:"Feature",geometry:{type:"Point",coordinates:[-1.26288597488275,51.7576388596821]},place_name:"OX1 2JD, Oxford, Oxfordshire, England, United Kingdom",properties:{title:"ENSO Drives interannual variation of forest woody growth across the tropics",countries:"United Kingdom",authorTitle:"Cecilia A L Dahlsj?",businessName:"University of Oxford"}},{type:"Feature",geometry:{type:"Point",coordinates:[-111.65511,35.19363]},place_name:"1899 PO Box, Flagstaff, Arizona 86011, United States",properties:{title:"ENSO Drives interannual variation of forest woody growth across the tropics",countries:"United States",authorTitle:"Christopher E Doughty",businessName:"Northern Arizona University"}},{type:"Feature",geometry:{type:"Point",coordinates:[-1.26288597488275,51.7576388596821]},place_name:"OX1 2JD, Oxford, Oxfordshire, England, United Kingdom",properties:{title:"ENSO Drives interannual variation of forest woody growth across the tropics",countries:"United Kingdom",authorTitle:"Erika Berenguer",businessName:"University of Oxford"}}]};
let result = business1.features.filter(({geometry:{ coordinates }}) =>
!b.has(s(coordinates)) && (b.add(s(coordinates)), true), b = new Set(), s = JSON.stringify)
console.log(result);
答案 1 :(得分：0)
我建议您使用lodash之类的库来简化生活。特别是lodash的uniqBy函数。我已经根据匹配的坐标进行了重复数据删除。完整的工作示例如下：
const featureCollection = {
"type": "FeatureCollection",
"features": [{
"type": "Feature",
"geometry": {
"type": "Point",
"coordinates": [
12.564111,
55.675659
]
},
"place_name": "Axeltorv 3, 1609 København, Denmark",
"properties": {
"title": "Comparison of Alternative Meat Inspection Regimes for Pigs From Non-Controlled Housing ? Considering the Cost of Error",
"countries": "Denmark",
"authorTitle": "Lis Alban",
"businessName": "Danish Agriculture and Food Council"
}
},
{
"type": "Feature",
"geometry": {
"type": "Point",
"coordinates": [
12.564111,
55.675659
]
},
"place_name": "Axeltorv 3, 1609 København, Denmark",
"properties": {
"title": "Comparison of Alternative Meat Inspection Regimes for Pigs From Non-Controlled Housing ? Considering the Cost of Error",
"countries": "Denmark",
"authorTitle": "Lisbeth Harm Nielsen",
"businessName": "Danish Agriculture and Food Council"
}
},
{
"type": "Feature",
"geometry": {
"type": "Point",
"coordinates": [-1.26288597488275,
51.7576388596821
]
},
"place_name": "OX1 2JD, Oxford, Oxfordshire, England, United Kingdom",
"properties": {
"title": "ENSO Drives interannual variation of forest woody growth across the tropics",
"countries": "United Kingdom",
"authorTitle": "C?cile A J Girardin",
"businessName": "University of Oxford"
}
},
{
"type": "Feature",
"geometry": {
"type": "Point",
"coordinates": [-1.26288597488275,
51.7576388596821
]
},
"place_name": "OX1 2JD, Oxford, Oxfordshire, England, United Kingdom",
"properties": {
"title": "ENSO Drives interannual variation of forest woody growth across the tropics",
"countries": "United Kingdom",
"authorTitle": "Cecilia A L Dahlsj?",
"businessName": "University of Oxford"
}
},
{
"type": "Feature",
"geometry": {
"type": "Point",
"coordinates": [-111.65511,
35.19363
]
},
"place_name": "1899 PO Box, Flagstaff, Arizona 86011, United States",
"properties": {
"title": "ENSO Drives interannual variation of forest woody growth across the tropics",
"countries": "United States",
"authorTitle": "Christopher E Doughty",
"businessName": "Northern Arizona University"
}
},
{
"type": "Feature",
"geometry": {
"type": "Point",
"coordinates": [-1.26288597488275,
51.7576388596821
]
},
"place_name": "OX1 2JD, Oxford, Oxfordshire, England, United Kingdom",
"properties": {
"title": "ENSO Drives interannual variation of forest woody growth across the tropics",
"countries": "United Kingdom",
"authorTitle": "Erika Berenguer",
"businessName": "University of Oxford"
}
}
],
};
featureCollection.features = _.uniqBy(featureCollection.features, (b) => b.geometry.coordinates[0] && b.geometry.coordinates[1]);
console.log(featureCollection);<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.11/lodash.js"></script>
答案 2 :(得分：0)
使用findIndex的简单过滤器就足够了
const business1 = {"type":"FeatureCollection","features":[{"type":"Feature","geometry":{"type":"Point","coordinates":[12.564111,55.675659]},"place_name":"Axeltorv 3, 1609 København, Denmark","properties":{"title":"Comparison of Alternative Meat Inspection Regimes for Pigs From Non-Controlled Housing ? Considering the Cost of Error","countries":"Denmark","authorTitle":"Lis Alban","businessName":"Danish Agriculture and Food Council"}},{"type":"Feature","geometry":{"type":"Point","coordinates":[12.564111,55.675659]},"place_name":"Axeltorv 3, 1609 København, Denmark","properties":{"title":"Comparison of Alternative Meat Inspection Regimes for Pigs From Non-Controlled Housing ? Considering the Cost of Error","countries":"Denmark","authorTitle":"Lisbeth Harm Nielsen","businessName":"Danish Agriculture and Food Council"}},{"type":"Feature","geometry":{"type":"Point","coordinates":[-1.26288597488275,51.7576388596821]},"place_name":"OX1 2JD, Oxford, Oxfordshire, England, United Kingdom","properties":{"title":"ENSO Drives interannual variation of forest woody growth across the tropics","countries":"United Kingdom","authorTitle":"C?cile A J Girardin","businessName":"University of Oxford"}},{"type":"Feature","geometry":{"type":"Point","coordinates":[-1.26288597488275,51.7576388596821]},"place_name":"OX1 2JD, Oxford, Oxfordshire, England, United Kingdom","properties":{"title":"ENSO Drives interannual variation of forest woody growth across the tropics","countries":"United Kingdom","authorTitle":"Cecilia A L Dahlsj?","businessName":"University of Oxford"}},{"type":"Feature","geometry":{"type":"Point","coordinates":[-111.65511,35.19363]},"place_name":"1899 PO Box, Flagstaff, Arizona 86011, United States","properties":{"title":"ENSO Drives interannual variation of forest woody growth across the tropics","countries":"United States","authorTitle":"Christopher E Doughty","businessName":"Northern Arizona University"}},{"type":"Feature","geometry":{"type":"Point","coordinates":[-1.26288597488275,51.7576388596821]},"place_name":"OX1 2JD, Oxford, Oxfordshire, England, United Kingdom","properties":{"title":"ENSO Drives interannual variation of forest woody growth across the tropics","countries":"United Kingdom","authorTitle":"Erika Berenguer","businessName":"University of Oxford"}}]};
business1.features = business1.features.filter(
({geometry:{coordinates:[lat,lon]}}, index, array) =>
array.findIndex(({geometry:{coordinates:[slat,slon]}}) =>
lat === slat && lon === slon) === index
);
console.log(business1)