类型SWIFT不同尺寸之间不能unsafeBitCast [英] can't unsafeBitCast between types of different sizes in swift
问题描述
当我试图找到阵副本,我得到的错误类型的不同尺寸之间不能unsafeBitCast。我发现下面的方法重复的。
FUNC uniq的< S:序列类型,T:哈希哪里S.Generator.Element == T>(来源:S) - GT; [T] {
VAR缓冲= [T]()
VAR添加=设置< T>()
在源ELEM {
如果!added.contains(ELEM){
buffer.append(ELEM)
added.insert(ELEM)
}
}
返回缓冲区
}FUNC过滤器(){
VAR arrayForSearch = mp3Files的! [串]
VAR filteredArray =的uniq(arrayForSearch)
的println(过滤阵列\\(filteredArray))
}
查找重复的方法,我知道这个链接<一个href=\"http://stackoverflow.com/questions/25738817/does-there-exist-within-swifts-api-an-easy-way-to-remove-duplicate-elements-fro\">enter这里的链接描述的。我使用的是X code 6和雨燕1.2
有这个code数组。
VAR mp3Files:阵列&LT;串GT ;!
FUNC exportData(){
VAR generalURL:[AnyObject]
VAR arrayFiles:阵列&LT; NSURL&GT;!
var目录= fileManager.URLsForDirectory(NSSearchPathDirectory.DocumentDirectory,inDomains:NSSearchPathDomainMask.UserDomainMask)
VAR urlFromDirectory = directory.first的! NSURL var文件= fileManager.contentsOfDirectoryAtURL(urlFromDirectory,includingPropertiesForKeys:无,选择:NSDirectoryEnumerationOptions.SkipsHiddenFiles,错误:无)!
的println(文件\\(文件)) mp3Files = file.map(){$ 0.lastPathComponent} .filter(){$ 0.pathExtension ==MP3} 的println(MP3文件\\(mp3Files))
}
当我在操场上写了这个code它的作品。
一个例子
VAR数组= [苹果,陆委会,iPhone,iPad的空气,苹果,空气,空]
VAR filteredArray =阵列(集(阵列))的println(filteredArray)
我如何使用它在我的项目呢?
VAR mp3Files:阵列&LT;串GT ;!
哇,这是一个很大的感叹号....他们没有必要的。
VAR arrayForSearch = mp3Files的! [串]
和类型 mp3Files
永远是相同的 [字符串]
,所以你不能强迫它们之间-cast(如果它让你就会崩溃)。
您是使用隐式展开自选方式过于频繁。它们只需要在某些特殊情况下。只要改变 mp3Files
到 [字符串]
(在这种情况下你不需要的作为!
可言;!你不应该需要为
经常其一) p>
同样, arrayFiles
(你永远不会使用),应该只是 [NSURL]
,而不是阵列&LT;!NSURL&GT; <!/ code>
when I try to find duplicates in array, I get the error "can't unsafeBitCast between types of different sizes". I find the duplicates following method.
func uniq<S : SequenceType, T : Hashable where S.Generator.Element == T>(source: S) -> [T] {
var buffer = [T]()
var added = Set<T>()
for elem in source {
if !added.contains(elem) {
buffer.append(elem)
added.insert(elem)
}
}
return buffer
}
func filter() {
var arrayForSearch = mp3Files as! [String]
var filteredArray = uniq(arrayForSearch)
println("filtered array \(filteredArray)")
}
The method of find duplicates I knew on this link enter link description here. I use Xcode 6 and Swift 1.2
There is the array in this code.
var mp3Files: Array<String!>!
func exportData() {
var generalURL: [AnyObject]?
var arrayFiles: Array<NSURL!>!
var directory = fileManager.URLsForDirectory(NSSearchPathDirectory.DocumentDirectory, inDomains: NSSearchPathDomainMask.UserDomainMask)
var urlFromDirectory = directory.first as! NSURL
var file = fileManager.contentsOfDirectoryAtURL(urlFromDirectory, includingPropertiesForKeys: nil, options: NSDirectoryEnumerationOptions.SkipsHiddenFiles, error: nil)!
println("file \(file)")
mp3Files = file.map(){ $0.lastPathComponent }.filter(){ $0.pathExtension == "mp3" }
println("mp3 files \(mp3Files)")
}
When I wrote this code in playground it works. An example
var array = ["Apple", "Mac", "iPhone", "iPad Air", "Apple", "Air", "Air"]
var filteredArray = Array(Set(array))
println(filteredArray)
How can I use it in my project?
var mp3Files: Array<String!>!
Wow, that's a lot of exclamation points.... They're not needed.
var arrayForSearch = mp3Files as! [String]
And the type of mp3Files
can never be the same as [String]
, so you can't force-cast between them (and would crash if it let you).
You're using implicitly unwrapped optionals way too often. They are only needed in some special cases. Just change mp3Files
to [String]
(in which case you won't need the as!
at all; you shouldn't need as!
very often either).
Similarly, arrayFiles
(which you never use), should just be [NSURL]
, not Array<NSURL!>!
.
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