我正在尝试将项目中的嵌套对象与相同的键组合在一起。
我在这里试了https://jsfiddle.net/Lpq6huvw/410/
输入数据：
Set {
Object {
"UserData": "/db/UserData/509c404f-ffa1-49d3-a161-b9eb5b2ebb14",
"UserDataPrivate": "/db/UserDataPrivate/26b7d879-4403-4135-ab44-b23e5244606b",
"UserStatus": "/db/UserStatus/cb50eae0-e254-4d8c-915a-674fd314fff3",
"createdAt": "2017-10-20T21:03:26.575Z",
"id": "/db/User/68",
"inactive": null,
"updatedAt": "2017-10-20T23:34:12.179Z",
"username": "15031111234",
"version": 4,
},
Object {
"UserData": "/db/UserData/a3dded63-4e0b-4841-b201-4c96dad1844d",
"UserDataPrivate": "/db/UserDataPrivate/6037a718-e33f-4945-b2d0-ca4c11fa4f13",
"UserStatus": null,
"createdAt": "2017-09-21T18:26:31.089Z",
"id": "/db/User/10",
"inactive": false,
"updatedAt": "2017-10-18T20:10:06.681Z",
"username": "15038304313",
"version": 19,
},
}
var searchbyID = propEq('id', '/db/User/10');
result = filter(searchbyID, test);
console.log(result)
进入这个数组：
public class MapsActivityy extends FragmentActivity implements OnMapReadyCallback {
private GoogleMap mMap;
LocationManager locationManager;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_maps_activityy);
// Obtain the SupportMapFragment and get notified when the map is ready to be used.
SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager()
.findFragmentById(R.id.map);
mapFragment.getMapAsync(this);
locationManager = (LocationManager) getSystemService(LOCATION_SERVICE);
//Permission to view el location
if (ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
// TODO: Consider calling
// ActivityCompat#requestPermissions
// here to request the missing permissions, and then overriding
// public void onRequestPermissionsResult(int requestCode, String[] permissions,
// int[] grantResults)
// to handle the case where the user grants the permission. See the documentation
// for ActivityCompat#requestPermissions for more details.
return;
}
//check lw el network provider enabled
//example vodafone or wi-fi
if(locationManager.isProviderEnabled(LocationManager.NETWORK_PROVIDER)){
locationManager.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, 0, 0, new LocationListener() {
@Override
public void onLocationChanged(Location location) {
//bngeeb el actual location
double latitude = location.getLatitude();
double longitude = location.getLongitude();
// latlng el location 3la el map
LatLng latLng = new LatLng(latitude,longitude);
//initalize class geocoder te3ml convert mn el lat wl lng to an address
Geocoder geocoder = new Geocoder(getApplicationContext());
try {
// 3shan n7ot el address fe list w max el results 1
List<Address> addressList= geocoder.getFromLocation(latitude,longitude,1);
String string = addressList.get(0).getCountryName()+" , ";
string +=addressList.get(0).getLocality()+" , ";
string +=addressList.get(0).getSubLocality();
//Hy7ot marker 3l location
mMap.addMarker(new MarkerOptions().position(latLng).title(string));
//3shan n3ml zoom 3l location
// el second val hwa amount of zoom
mMap.moveCamera(CameraUpdateFactory.newLatLngZoom(latLng,15.2f));
} catch (IOException e) {
e.printStackTrace();
}
}
@Override
public void onStatusChanged(String s, int i, Bundle bundle) {
}
@Override
public void onProviderEnabled(String s) {
}
@Override
public void onProviderDisabled(String s) {
}
});
}
//Satellite
else if(locationManager.isProviderEnabled(LocationManager.GPS_PROVIDER)){
locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0, new LocationListener() {
@Override
public void onLocationChanged(Location location) {
//bngeeb el actual location
double latitude = location.getLatitude();
double longitude = location.getLongitude();
// latlng el location 3la el map
LatLng latLng = new LatLng(latitude,longitude);
//initalize class geocoder te3ml convert mn el lat wl lng to an address
Geocoder geocoder = new Geocoder(getApplicationContext());
try {
// 3shan n7ot el address fe list w max el results 1
List<Address> addressList= geocoder.getFromLocation(latitude,longitude,1);
String string = addressList.get(0).getCountryName()+" , ";
string +=addressList.get(0).getLocality()+" , ";
//if available hygeeb subLoc if not hyb3t null
string +=addressList.get(0).getSubLocality();
//Hy7ot marker 3l location
mMap.addMarker(new MarkerOptions().position(latLng).title(string));
//3shan n3ml zoom 3l location
// el second val hwa amount of zoom
mMap.moveCamera(CameraUpdateFactory.newLatLngZoom(latLng,15.2f));
} catch (IOException e) {
e.printStackTrace();
}
}
@Override
public void onStatusChanged(String s, int i, Bundle bundle) {
}
@Override
public void onProviderEnabled(String s) {
}
@Override
public void onProviderDisabled(String s) {
}
});
}
}
/**
* Manipulates the map once available.
* This callback is triggered when the map is ready to be used.
* This is where we can add markers or lines, add listeners or move the camera. In this case,
* we just add a marker near Sydney, Australia.
* If Google Play services is not installed on the device, the user will be prompted to install
* it inside the SupportMapFragment. This method will only be triggered once the user has
* installed Google Play services and returned to the app.
*/
@Override
public void onMapReady(GoogleMap googleMap) {
mMap = googleMap;
// Add a marker in Sydney and move the camera
/* LatLng sydney = new LatLng(-34, 151);
mMap.addMarker(new MarkerOptions().position(sydney).title("Marker in Sydney"));
mMap.moveCamera(CameraUpdateFactory.newLatLng(sydney));*/
}
}
我在下面尝试了这个，它将所有重复的项目映射为一个对象。但是，我希望它在每个“顶级”前身下映射。
[{
"a": "Mon",
"type": [{
"b": 1
}, {
"b": 3
}]
}, {
"a": "Mon",
"type": [{
"b": 2
}]
}, {
"a": "Tue",
"type": [{
"b": 40
}]
}, {
"a": "Tue",
"type": [{
"b": 50
}]
}, {
"a": "Wed",
"type": [{
"b": 30
}]
}]
答案 0 :(得分：2)
我个人认为Javascript内置的函数运行良好，并且比一些lodash函数更容易理解。
例如
var data = [{"a":"Mon","type":[{"b":1},{"b":3}]},{"a":"Mon","type":[{"b":2},{"b":3}]},{"a":"Tue","type":[{"b":40}]},{"a":"Tue","type":[{"b":50}]},{"a":"Wed","type":[{"b":30}]}];
var result = data.reduce((acc, val) => {
var found = acc.find((findval) => val.a === findval.a);
if (!found) acc.push(val)
else found.type = found.type.concat(
val.type.filter((f) => !found.type.find((findval) => f.b === findval.b)));
return acc;
}, []);
console.log(result);
答案 1 :(得分：1)
这是一个没有lodash的答案：
function combine (input) {
const hash = input.reduce((result, current) => {
if (result[current['a']]) {
result[current['a']] = result[current['a']].concat(current['type'])
} else {
result[current['a']] = current['type']
}
return result
}, {})
return Object.keys(hash).map(key => {
return {
a: key,
type: hash[key]
}
})
}
答案 2 :(得分：1)
ES6 ：您可以使用Array＃reduce进行迭代，将项目收集到Map中，然后使用扩展语法和Map＃值转换回数组：
const data = [{"a":"Mon","type":[{"b":1},{"b":3}]},{"a":"Mon","type":[{"b":2}]},{"a":"Tue","type":[{"b":40}]},{"a":"Tue","type":[{"b":50}]},{"a":"Wed","type":[{"b":30}]}];
const result = [...data.reduce((m, { a, type }) => {
const item = m.get(a) || { a, type: [] }; // use a Set to maintain uniqueness
item.type.push(...type);
return m.set(a, item);
}, new Map).values()]
.map(({ a, type }) => ({ // make types unique again
a,
type: [...type.reduce((m, o) => m.has(o.b) ? m : m.set(o.b, o), new Map).values()]
}));
console.log(result);
Lodash ：使用_.groupBy()在一个组中获取具有相同a属性的所有对象。映射组，并使用_.mergeWith()合并每个组，并连接所有type数组。
使用map进行另一次传递，以使type数组中的所有项目都是唯一的。
const data = [{"a":"Mon","type":[{"b":1},{"b":3}]},{"a":"Mon","type":[{"b":2}]},{"a":"Tue","type":[{"b":40}]},{"a":"Tue","type":[{"b":50}]},{"a":"Wed","type":[{"b":30}]}];
const result = _(data)
.groupBy('a')
.map((group) => _.mergeWith({}, ...group, ((objValue, srcValue, key) =>
key === 'type' ? (objValue || []).concat(srcValue) : undefined
)))
.map((obj) => Object.assign(obj, { type: _.uniq(obj.type) }))
.value();
console.log(result);<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.4/lodash.min.js"></script>