Mixing
Getting An Arbitrary Type From Reduce
I'm doing a very simple operation. I'm sorting through a bunch of locations in a map to create an enclosing circle, like so:
var maxLong: Double = -180
var maxLat: Double = -180
var minLong: Double = 180
var minLat: Double = 180
for coord in inCoordinates {
maxLong = max(coord.longitude, maxLong)
maxLat = max(coord.latitude, maxLat)
minLong = min(coord.longitude, minLong)
minLat = min(coord.latitude, minLat)
}
let nw: CLLocation = CLLocation(latitude: maxLat, longitude: minLong)
let se: CLLocation = CLLocation(latitude: minLat, longitude: maxLong)
let center = CLLocationCoordinate2D(latitude: (maxLat + minLat) / 2.0, longitude: (maxLong + minLong) / 2.0)
let radiusInMeters = abs(nw.distance(from: se)) / 2.0
return MKCircle(center: center, radius: radiusInMeters)
Pretty straightforward (Yeah, I know about the IDL issue, but I want to keep this simple).
What I'd like to know, is if there were some way I could boil the loop into a variant of reduce, where you would end up with something like this:
let enclosingRect: MKMapRect = inCoordinates.magikalReduce {
// Magic Happens Here -Queue Doug Henning GIF
}
So the returned rect contains the distilled points.
Yeah, I know that I can simply extend Array (with maybe a type qualifier) to do this with a calculated property, but that sort of defeats the purpose of this. The above is fairly efficient, and I'd rather not add overhead, just to be fancy (Which means, even if I could do it, it might be too inefficient to use).
This is more of a curiosity exploration than a technical need. The above code does fine for me, and is relatively zippy.
swift algorithm mapkit reduce
asked Nov 20 '18 at 18:57
Little Green ViperLittle Green Viper
2,05842743
add a comment |
I'm doing a very simple operation. I'm sorting through a bunch of locations in a map to create an enclosing circle, like so:
var maxLong: Double = -180
var maxLat: Double = -180
var minLong: Double = 180
var minLat: Double = 180
for coord in inCoordinates {
maxLong = max(coord.longitude, maxLong)
maxLat = max(coord.latitude, maxLat)
minLong = min(coord.longitude, minLong)
minLat = min(coord.latitude, minLat)
}
let nw: CLLocation = CLLocation(latitude: maxLat, longitude: minLong)
let se: CLLocation = CLLocation(latitude: minLat, longitude: maxLong)
let center = CLLocationCoordinate2D(latitude: (maxLat + minLat) / 2.0, longitude: (maxLong + minLong) / 2.0)
let radiusInMeters = abs(nw.distance(from: se)) / 2.0
return MKCircle(center: center, radius: radiusInMeters)
Pretty straightforward (Yeah, I know about the IDL issue, but I want to keep this simple).
What I'd like to know, is if there were some way I could boil the loop into a variant of reduce, where you would end up with something like this:
let enclosingRect: MKMapRect = inCoordinates.magikalReduce {
// Magic Happens Here -Queue Doug Henning GIF
}
So the returned rect contains the distilled points.
Yeah, I know that I can simply extend Array (with maybe a type qualifier) to do this with a calculated property, but that sort of defeats the purpose of this. The above is fairly efficient, and I'd rather not add overhead, just to be fancy (Which means, even if I could do it, it might be too inefficient to use).
This is more of a curiosity exploration than a technical need. The above code does fine for me, and is relatively zippy.
swift algorithm mapkit reduce
asked Nov 20 '18 at 18:57
Little Green ViperLittle Green Viper
2,05842743
add a comment |
I'm doing a very simple operation. I'm sorting through a bunch of locations in a map to create an enclosing circle, like so:
var maxLong: Double = -180
var maxLat: Double = -180
var minLong: Double = 180
var minLat: Double = 180
for coord in inCoordinates {
maxLong = max(coord.longitude, maxLong)
maxLat = max(coord.latitude, maxLat)
minLong = min(coord.longitude, minLong)
minLat = min(coord.latitude, minLat)
}
let nw: CLLocation = CLLocation(latitude: maxLat, longitude: minLong)
let se: CLLocation = CLLocation(latitude: minLat, longitude: maxLong)
let center = CLLocationCoordinate2D(latitude: (maxLat + minLat) / 2.0, longitude: (maxLong + minLong) / 2.0)
let radiusInMeters = abs(nw.distance(from: se)) / 2.0
return MKCircle(center: center, radius: radiusInMeters)
Pretty straightforward (Yeah, I know about the IDL issue, but I want to keep this simple).
What I'd like to know, is if there were some way I could boil the loop into a variant of reduce, where you would end up with something like this:
let enclosingRect: MKMapRect = inCoordinates.magikalReduce {
// Magic Happens Here -Queue Doug Henning GIF
}
So the returned rect contains the distilled points.
Yeah, I know that I can simply extend Array (with maybe a type qualifier) to do this with a calculated property, but that sort of defeats the purpose of this. The above is fairly efficient, and I'd rather not add overhead, just to be fancy (Which means, even if I could do it, it might be too inefficient to use).
This is more of a curiosity exploration than a technical need. The above code does fine for me, and is relatively zippy.
swift algorithm mapkit reduce
asked Nov 20 '18 at 18:57
Little Green ViperLittle Green Viper
2,05842743
I'm doing a very simple operation. I'm sorting through a bunch of locations in a map to create an enclosing circle, like so:
var maxLong: Double = -180
var maxLat: Double = -180
var minLong: Double = 180
var minLat: Double = 180
for coord in inCoordinates {
maxLong = max(coord.longitude, maxLong)
maxLat = max(coord.latitude, maxLat)
minLong = min(coord.longitude, minLong)
minLat = min(coord.latitude, minLat)
}
let nw: CLLocation = CLLocation(latitude: maxLat, longitude: minLong)
let se: CLLocation = CLLocation(latitude: minLat, longitude: maxLong)
let center = CLLocationCoordinate2D(latitude: (maxLat + minLat) / 2.0, longitude: (maxLong + minLong) / 2.0)
let radiusInMeters = abs(nw.distance(from: se)) / 2.0
return MKCircle(center: center, radius: radiusInMeters)
Pretty straightforward (Yeah, I know about the IDL issue, but I want to keep this simple).
What I'd like to know, is if there were some way I could boil the loop into a variant of reduce, where you would end up with something like this:
let enclosingRect: MKMapRect = inCoordinates.magikalReduce {
// Magic Happens Here -Queue Doug Henning GIF
}
So the returned rect contains the distilled points.
Yeah, I know that I can simply extend Array (with maybe a type qualifier) to do this with a calculated property, but that sort of defeats the purpose of this. The above is fairly efficient, and I'd rather not add overhead, just to be fancy (Which means, even if I could do it, it might be too inefficient to use).
This is more of a curiosity exploration than a technical need. The above code does fine for me, and is relatively zippy.
swift algorithm mapkit reduce
swift algorithm mapkit reduce
asked Nov 20 '18 at 18:57
Little Green ViperLittle Green Viper
2,05842743
asked Nov 20 '18 at 18:57
Little Green ViperLittle Green Viper
2,05842743
asked Nov 20 '18 at 18:57
Little Green ViperLittle Green Viper
2,05842743
asked Nov 20 '18 at 18:57
Little Green ViperLittle Green Viper
2,05842743
asked Nov 20 '18 at 18:57
Little Green ViperLittle Green Viper
2,05842743
2,05842743
add a comment |
add a comment |
2 Answers
2
active
oldest
votes
Do you mean
// calculate the enclosing rect with `reduce` and `union`, you have to create an `MKMapRect` from each coordinate
let enclosingRect = inCoordinates.reduce(MKMapRect.null) { $0.union(MKMapRect(origin: MKMapPoint($1), size: MKMapSize())) }
answered Nov 20 '18 at 19:29
vadianvadian
146k13158175
This is really what I was looking for. Good show!
– Little Green Viper
Nov 20 '18 at 19:33
OrinCoordinates.reduce(MKMapRect.null) { $0.union(MKMapRect(origin: MKMapPoint($1), size: MKMapSize())) }without an intermediate array.
– Martin R
Nov 20 '18 at 19:51
@MartinR That's indeed better, thanks.
– vadian
Nov 20 '18 at 19:53
add a comment |
You can create a struct for holding the min/max longitude and latitude values, then use reduce, where you use the initial values for these for creating an initial result, then creating an updated version of the struct with the necessary min/max calculations.
struct MinMaxCoordinates {
let maxLong:Double
let maxLat:Double
let minLong:Double
let minLat:Double
}
let minMaxCoordinates = inCoordinates.reduce(MinMaxCoordinates(maxLong: -180, maxLat: -180, minLong: 180, minLat: 180), {minMax, coord in
return MinMaxCoordinates(maxLong: max(minMax.maxLong, coord.longitude), maxLat: max(minMax.maxLat, coord.latitude), minLong: min(minMax.minLong, coord.longitude), minLat: max(minMax.minLat, coord.latitude))
})
let nw: CLLocation = CLLocation(latitude: minMaxCoordinates.maxLat, longitude: minMaxCoordinates.minLong)
let se: CLLocation = CLLocation(latitude: minMaxCoordinates.minLat, longitude: minMaxCoordinates.maxLong)
let center = CLLocationCoordinate2D(latitude: (minMaxCoordinates.maxLat + minMaxCoordinates.minLat) / 2.0, longitude: (minMaxCoordinates.maxLong + minMaxCoordinates.minLong) / 2.0)
let radiusInMeters = abs(nw.distance(from: se)) / 2.0
return MKCircle(center: center, radius: radiusInMeters)
answered Nov 20 '18 at 19:31
Dávid PásztorDávid Pásztor
21.5k82749
add a comment |
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2 Answers
2
active
oldest
votes
2 Answers
2
active
oldest
votes
active
oldest
votes
active
oldest
votes
Do you mean
// calculate the enclosing rect with `reduce` and `union`, you have to create an `MKMapRect` from each coordinate
let enclosingRect = inCoordinates.reduce(MKMapRect.null) { $0.union(MKMapRect(origin: MKMapPoint($1), size: MKMapSize())) }
answered Nov 20 '18 at 19:29
vadianvadian
146k13158175
This is really what I was looking for. Good show!
– Little Green Viper
Nov 20 '18 at 19:33
OrinCoordinates.reduce(MKMapRect.null) { $0.union(MKMapRect(origin: MKMapPoint($1), size: MKMapSize())) }without an intermediate array.
– Martin R
Nov 20 '18 at 19:51
@MartinR That's indeed better, thanks.
– vadian
Nov 20 '18 at 19:53
add a comment |
Do you mean
// calculate the enclosing rect with `reduce` and `union`, you have to create an `MKMapRect` from each coordinate
let enclosingRect = inCoordinates.reduce(MKMapRect.null) { $0.union(MKMapRect(origin: MKMapPoint($1), size: MKMapSize())) }
answered Nov 20 '18 at 19:29
vadianvadian
146k13158175
This is really what I was looking for. Good show!
– Little Green Viper
Nov 20 '18 at 19:33
OrinCoordinates.reduce(MKMapRect.null) { $0.union(MKMapRect(origin: MKMapPoint($1), size: MKMapSize())) }without an intermediate array.
– Martin R
Nov 20 '18 at 19:51
@MartinR That's indeed better, thanks.
– vadian
Nov 20 '18 at 19:53
add a comment |
Do you mean
// calculate the enclosing rect with `reduce` and `union`, you have to create an `MKMapRect` from each coordinate
let enclosingRect = inCoordinates.reduce(MKMapRect.null) { $0.union(MKMapRect(origin: MKMapPoint($1), size: MKMapSize())) }
answered Nov 20 '18 at 19:29
vadianvadian
146k13158175
Do you mean
// calculate the enclosing rect with `reduce` and `union`, you have to create an `MKMapRect` from each coordinate
let enclosingRect = inCoordinates.reduce(MKMapRect.null) { $0.union(MKMapRect(origin: MKMapPoint($1), size: MKMapSize())) }
answered Nov 20 '18 at 19:29
vadianvadian
146k13158175
edited Nov 20 '18 at 19:53
answered Nov 20 '18 at 19:29
vadianvadian
146k13158175
answered Nov 20 '18 at 19:29
vadianvadian
146k13158175
answered Nov 20 '18 at 19:29
vadianvadian
146k13158175
146k13158175
This is really what I was looking for. Good show!
– Little Green Viper
Nov 20 '18 at 19:33
OrinCoordinates.reduce(MKMapRect.null) { $0.union(MKMapRect(origin: MKMapPoint($1), size: MKMapSize())) }without an intermediate array.
– Martin R
Nov 20 '18 at 19:51
@MartinR That's indeed better, thanks.
– vadian
Nov 20 '18 at 19:53
add a comment |
This is really what I was looking for. Good show!
– Little Green Viper
Nov 20 '18 at 19:33
OrinCoordinates.reduce(MKMapRect.null) { $0.union(MKMapRect(origin: MKMapPoint($1), size: MKMapSize())) }without an intermediate array.
– Martin R
Nov 20 '18 at 19:51
@MartinR That's indeed better, thanks.
– vadian
Nov 20 '18 at 19:53
This is really what I was looking for. Good show!
– Little Green Viper
Nov 20 '18 at 19:33
This is really what I was looking for. Good show!
– Little Green Viper
Nov 20 '18 at 19:33
Or
inCoordinates.reduce(MKMapRect.null) { $0.union(MKMapRect(origin: MKMapPoint($1), size: MKMapSize())) } without an intermediate array.– Martin R
Nov 20 '18 at 19:51
Or
inCoordinates.reduce(MKMapRect.null) { $0.union(MKMapRect(origin: MKMapPoint($1), size: MKMapSize())) } without an intermediate array.– Martin R
Nov 20 '18 at 19:51
@MartinR That's indeed better, thanks.
– vadian
Nov 20 '18 at 19:53
@MartinR That's indeed better, thanks.
– vadian
Nov 20 '18 at 19:53
add a comment |
You can create a struct for holding the min/max longitude and latitude values, then use reduce, where you use the initial values for these for creating an initial result, then creating an updated version of the struct with the necessary min/max calculations.
struct MinMaxCoordinates {
let maxLong:Double
let maxLat:Double
let minLong:Double
let minLat:Double
}
let minMaxCoordinates = inCoordinates.reduce(MinMaxCoordinates(maxLong: -180, maxLat: -180, minLong: 180, minLat: 180), {minMax, coord in
return MinMaxCoordinates(maxLong: max(minMax.maxLong, coord.longitude), maxLat: max(minMax.maxLat, coord.latitude), minLong: min(minMax.minLong, coord.longitude), minLat: max(minMax.minLat, coord.latitude))
})
let nw: CLLocation = CLLocation(latitude: minMaxCoordinates.maxLat, longitude: minMaxCoordinates.minLong)
let se: CLLocation = CLLocation(latitude: minMaxCoordinates.minLat, longitude: minMaxCoordinates.maxLong)
let center = CLLocationCoordinate2D(latitude: (minMaxCoordinates.maxLat + minMaxCoordinates.minLat) / 2.0, longitude: (minMaxCoordinates.maxLong + minMaxCoordinates.minLong) / 2.0)
let radiusInMeters = abs(nw.distance(from: se)) / 2.0
return MKCircle(center: center, radius: radiusInMeters)
answered Nov 20 '18 at 19:31
Dávid PásztorDávid Pásztor
21.5k82749
add a comment |
You can create a struct for holding the min/max longitude and latitude values, then use reduce, where you use the initial values for these for creating an initial result, then creating an updated version of the struct with the necessary min/max calculations.
struct MinMaxCoordinates {
let maxLong:Double
let maxLat:Double
let minLong:Double
let minLat:Double
}
let minMaxCoordinates = inCoordinates.reduce(MinMaxCoordinates(maxLong: -180, maxLat: -180, minLong: 180, minLat: 180), {minMax, coord in
return MinMaxCoordinates(maxLong: max(minMax.maxLong, coord.longitude), maxLat: max(minMax.maxLat, coord.latitude), minLong: min(minMax.minLong, coord.longitude), minLat: max(minMax.minLat, coord.latitude))
})
let nw: CLLocation = CLLocation(latitude: minMaxCoordinates.maxLat, longitude: minMaxCoordinates.minLong)
let se: CLLocation = CLLocation(latitude: minMaxCoordinates.minLat, longitude: minMaxCoordinates.maxLong)
let center = CLLocationCoordinate2D(latitude: (minMaxCoordinates.maxLat + minMaxCoordinates.minLat) / 2.0, longitude: (minMaxCoordinates.maxLong + minMaxCoordinates.minLong) / 2.0)
let radiusInMeters = abs(nw.distance(from: se)) / 2.0
return MKCircle(center: center, radius: radiusInMeters)
answered Nov 20 '18 at 19:31
Dávid PásztorDávid Pásztor
21.5k82749
add a comment |
You can create a struct for holding the min/max longitude and latitude values, then use reduce, where you use the initial values for these for creating an initial result, then creating an updated version of the struct with the necessary min/max calculations.
struct MinMaxCoordinates {
let maxLong:Double
let maxLat:Double
let minLong:Double
let minLat:Double
}
let minMaxCoordinates = inCoordinates.reduce(MinMaxCoordinates(maxLong: -180, maxLat: -180, minLong: 180, minLat: 180), {minMax, coord in
return MinMaxCoordinates(maxLong: max(minMax.maxLong, coord.longitude), maxLat: max(minMax.maxLat, coord.latitude), minLong: min(minMax.minLong, coord.longitude), minLat: max(minMax.minLat, coord.latitude))
})
let nw: CLLocation = CLLocation(latitude: minMaxCoordinates.maxLat, longitude: minMaxCoordinates.minLong)
let se: CLLocation = CLLocation(latitude: minMaxCoordinates.minLat, longitude: minMaxCoordinates.maxLong)
let center = CLLocationCoordinate2D(latitude: (minMaxCoordinates.maxLat + minMaxCoordinates.minLat) / 2.0, longitude: (minMaxCoordinates.maxLong + minMaxCoordinates.minLong) / 2.0)
let radiusInMeters = abs(nw.distance(from: se)) / 2.0
return MKCircle(center: center, radius: radiusInMeters)
answered Nov 20 '18 at 19:31
Dávid PásztorDávid Pásztor
21.5k82749
You can create a struct for holding the min/max longitude and latitude values, then use reduce, where you use the initial values for these for creating an initial result, then creating an updated version of the struct with the necessary min/max calculations.
struct MinMaxCoordinates {
let maxLong:Double
let maxLat:Double
let minLong:Double
let minLat:Double
}
let minMaxCoordinates = inCoordinates.reduce(MinMaxCoordinates(maxLong: -180, maxLat: -180, minLong: 180, minLat: 180), {minMax, coord in
return MinMaxCoordinates(maxLong: max(minMax.maxLong, coord.longitude), maxLat: max(minMax.maxLat, coord.latitude), minLong: min(minMax.minLong, coord.longitude), minLat: max(minMax.minLat, coord.latitude))
})
let nw: CLLocation = CLLocation(latitude: minMaxCoordinates.maxLat, longitude: minMaxCoordinates.minLong)
let se: CLLocation = CLLocation(latitude: minMaxCoordinates.minLat, longitude: minMaxCoordinates.maxLong)
let center = CLLocationCoordinate2D(latitude: (minMaxCoordinates.maxLat + minMaxCoordinates.minLat) / 2.0, longitude: (minMaxCoordinates.maxLong + minMaxCoordinates.minLong) / 2.0)
let radiusInMeters = abs(nw.distance(from: se)) / 2.0
return MKCircle(center: center, radius: radiusInMeters)
answered Nov 20 '18 at 19:31
Dávid PásztorDávid Pásztor
21.5k82749
answered Nov 20 '18 at 19:31
Dávid PásztorDávid Pásztor
21.5k82749
answered Nov 20 '18 at 19:31
Dávid PásztorDávid Pásztor
21.5k82749
answered Nov 20 '18 at 19:31
Dávid PásztorDávid Pásztor
21.5k82749
21.5k82749
add a comment |
add a comment |
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