[英]swift convert Range<Int> to [Int]
how to convert Range to Array 如何将Range转换为Array
I tried: 我试过了:
let min = 50
let max = 100
let intArray:[Int] = (min...max)
get error Range<Int> is not convertible to [Int]
获取错误
Range<Int> is not convertible to [Int]
I also tried: 我也尝试过:
let intArray:[Int] = [min...max]
and 和
let intArray:[Int] = (min...max) as [Int]
they don't work either. 他们也不工作。
您需要创建一个Array<Int>
使用Range<Int>
,而不是投荷兰国际集团它。
let intArray: [Int] = Array(min...max)
将Range放在init中。
let intArray = [Int](min...max)
I figured it out: 我想到了:
let intArray = [Int](min...max)
Giving credit to someone else. 给予别人信任。
do: 做:
let intArray = Array(min...max)
This should work because Array
has an initializer taking a SequenceType
and Range
conforms to SequenceType
. 这应该有效,因为
Array
有一个初始化器,它使SequenceType
和Range
符合SequenceType
。
Use map
使用
map
let min = 50
let max = 100
let intArray = (min...max).map{$0}
Interesting that you cannot (at least, with Swift 3 and Xcode 8) use Range<Int>
object directly: 有趣的是你不能(至少使用Swift 3和Xcode 8)直接使用
Range<Int>
对象:
let range: Range<Int> = 1...10
let array: [Int] = Array(range) // Error: "doesn't conform to expected type 'Sequence'"
Therefore, as it was mentioned earlier, you need to manually "unwrap" you range like: 因此,如前所述,您需要手动“展开”您的范围,如:
let array: [Int] = Array(range.lowerBound...range.upperBound)
Ie, you can use literal only. 即,您只能使用文字。
Since Swift 3/Xcode 8 there is a CountableRange
type, which can be handy: 由于Swift 3 / Xcode 8有一个
CountableRange
类型,它可以很方便:
let range: CountableRange<Int> = -10..<10
let array = Array(range)
print(array)
// prints:
// [-10, -9, -8, -7, -6, -5, -4, -3, -2, -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
It can be used directly in for
- in
loops: 它可以直接
for
- in
循环:
for i in range {
print(i)
}
You can implement ClosedRange & Range instance intervals with reduce() in functions like this. 您可以使用reduce()在这样的函数中实现ClosedRange和Range实例间隔。
func sumClosedRange(_ n: ClosedRange<Int>) -> Int {
return n.reduce(0, +)
}
sumClosedRange(1...10) // 55
func sumRange(_ n: Range<Int>) -> Int {
return n.reduce(0, +)
}
sumRange(1..<11) // 55
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