我试图转换以下
Swift 2.3代码：
//Example usage:
//(0 ..< 778).binarySearch { $0 < 145 } // 145
extension CollectionType where Index: RandomAccessIndexType {
/// Finds such index N that predicate is true for all elements up to
/// but not including the index N,and is false for all elements
/// starting with index N.
/// Behavior is undefined if there is no such N.
func binarySearch(predicate: Generator.Element -> Bool)
-> Index {
var low = startIndex
var high = endIndex
while low != high {
let mid = low.advancedBy(low.distanceTo(high) / 2)
if predicate(self[mid]) {
low = mid.advancedBy(1)
} else {
high = mid
}
}
return low
}
}
进入Swift 3如下：
//Example usage:
//(0 ..< 778).binarySearch { $0 < 145 } // 145
extension Collection where Index: Strideable {
/// Finds such index N that predicate is true for all elements up to
/// but not including the index N,and is false for all elements
/// starting with index N.
/// Behavior is undefined if there is no such N.
func binarySearch(predicate: (Generator.Element) -> Bool)
-> Index {
var low = startIndex
var high = endIndex
while low != high {
let mid = low.advanced(by: low.distance(to: high) / 2)
if predicate(self[mid]) {
low = mid.advanced(to: 1)
} else {
high = mid
}
}
return low
}
}
Binary operator ‘/’ cannot be applied to operands of type ‘self.Index.Stride’ and ‘Int’
抛出让mid = low.advanced(by：low.distance(to：high)/ 2)
有关如何修复它的任何帮助？
在Swift 3中,“集合移动他们的索引”,比较
关于Swift进化的 A New Model for Collections and Indices.特别是,您不要在索引上调用advancedBy(),
但是在集合上使用index()方法来推进索引.
关于Swift进化的 A New Model for Collections and Indices.特别是,您不要在索引上调用advancedBy(),
但是在集合上使用index()方法来推进索引.
所以你的方法将在Swift 3中实现
extension Collection {
func binarySearch(predicate: (Iterator.Element) -> Bool) -> Index {
var low = startIndex
var high = endIndex
while low != high {
let mid = index(low,offsetBy: distance(from: low,to: high)/2)
if predicate(self[mid]) {
low = index(after: mid)
} else {
high = mid
}
}
return low
}
}
不需要对索引类型进行任何限制.
