在 Swift 中创建一个数组数组

Question

我有两个数组：

var latitude = [100,200,300]
var longitude = [55,66,77]

我正在尝试制作这个新数组：

var coordinate = [[100,55],[200,66],[300,77]]

但它不起作用。这是我的代码：

var latitude = [100,200,300]
var longitude = [55,66,77]



var x = 0
var y = 0
var coordinate = []

for lat in latitude{
    x = lat

    for long in longitude{
        y = long
    }

    coordinate = [x,y]

}

coor

这是我得到的：

[300,77]

只有最后两个元素。

Answer 1

试试这个代码：

var latitude = [100,200,300]
var longitude = [55,66,77]

var x = 0
var y = 0
var coordinate = Array<Array<Int>>()

var i = 0
for lat in latitude{
    x = lat
    y = longitude[i++]

    coordinate.append(Array(x,y))
}

---

var latitude = [100,200,300]
var longitude = [55,66,77]

var coordinate = Array<Array<Int>>()

for (lat,lon) in zip(latitude,longitude){
    coordinate.append(Array(arrayLiteral: lat,lon))
}

Answer 2

这里有一个建议。 cmets 在代码中。

var latitude = [100,200,300] // OK, so these are arrays of Ints
var longitude = [55,66,77] // Is that what you want? Doubles or floats might be more appropriate

var x = 0 // Why declare these out here? In the loop is ok
var y = 0 // You are also forcing them to Ints (and vars, not lets, though you're not changing them)

/* This IS a bit of a mess
for lat in latitude{
    x = lat // This should be ok, but no need to declare x outside the loop

    for long in longitude { // This is wrong - you will always get the last longitude
        y = long
    }

    coordinate = [x,y] // where is coordinate declared, and as what?
}
*/

// I'm not sure why you want an array of arrays - an array of tuples,
// or an array of structs seems more correct, as there will only ever be two elements
// in the inner "array". Here's a struct...
struct Coordinate {
    var latitude : Int // As I said above, doubles might be better
    var longitude : Int
}

var coordinates = Coordinate[]()
if latitude.count == longitude.count {
    for i in 0..latitude.count {
        coordinates += Coordinate(latitude:latitude[i], longitude:longitude[i])
    }
    println("Coordinates = \(coordinates)")
} else {
    println("Mismatch in length of ordinate arrays")
}

---

要使用数组数组（这是实际问题），请考虑这个

typealias IntArray = Array<Int> // Again, probably should be doubles...
var coordinateArray = IntArray[]()
for i in 0..min(latitude.count, longitude.count) { 
    coordinateArray += [latitude[i], longitude[i]]
}

Answer 3

你应该尝试定义Array允许存储的类型，并且类型应该是Dictionary

类似这样的：

var latitude: Float[] = [100,200,300]
var longitude: Float[] = [55,66,77]

var coordinate = Array<Dictionary>()
var i: Int = 0;
for lat in latitude {
    let coor: Dictionary<String, Float> = ["x":lat, "y": longitude[i]]
    coordinate.append(coor)
    i++;
}