在Swift 2.0中将字符转换为Int [英] Convert Character to Int in Swift 2.0

问题描述

我只想将字符转换为 Int 。

这应该很简单。但我还没有发现以前的答案有帮助。总是有一些错误。也许是因为我在Swift 2.0中尝试它。

  for i in（unsolved.characters）{
 fileLines + = String（i）.toInt $ b print（i）
} 
  

解决方案

在Swift 2.0中， toInt（）等已被替换为初始化器。 （在这种情况下， Int（someString）。）

因为不是所有的字符串都可以转换为int （ Int？），而不只是一个<$ c $ c> Int 。最好的办法是使用如果let 解开这个可选项。

但是这个代码在Swift 2中工作，并且完成我想要做的事情：

  let unsolved =123abc
 
 var fileLines = [Int]（）
 
 for un in unsolved.characters {
 let someString = String（i）
 if let someInt = Int（someString）{
 fileLines + = [someInt] 
} 
 print（i）
} 
  pre> 
 
 
或者，对于Swiftier解决方案：
  let unsolved = 123abc
 
 let fileLines = unsolved.characters.filter（{Int（String（$ 0））！= nil}）map（{Int（String（$ 0））！}）
 
 // fileLines = [1，2，3] 
  
与 flatMap ：
  let fileLines = unsolved.characters.flatMap {Int （String（$ 0））} 
  
  flatMap 返回数组包含映射 transform 的非nil结果 self ...所以当 Int（String（$ 0））是 nil 时， / p> 
I just want to convert a character into an Int. 

This should be simple. But I haven't found the previous answers helpful. There is always some error. Perhaps it is because I'm trying it in Swift 2.0. 
for i in (unsolved.characters) {
  fileLines += String(i).toInt()
  print(i)
}

解决方案
In Swift 2.0, toInt(), etc., have been replaced with initializers. (In this case, Int(someString).)

Because not all strings can be converted to ints, this initializer is failable,  which means it returns an optional int (Int?) instead of just an Int. The best thing to do is unwrap this optional using if let.

I'm not sure exactly what you're going for, but this code works in Swift 2, and accomplishes what I think you're trying to do:
let unsolved = "123abc"

var fileLines = [Int]()

for i in unsolved.characters {
    let someString = String(i)
    if let someInt = Int(someString) {
        fileLines += [someInt]
    }
    print(i)
}
Or, for a Swiftier solution:
let unsolved = "123abc"

let fileLines = unsolved.characters.filter({ Int(String($0)) != nil }).map({ Int(String($0))! })

// fileLines = [1, 2, 3]
You can shorten this more with flatMap:
let fileLines = unsolved.characters.flatMap { Int(String($0)) }
flatMap returns "an Array containing the non-nil results of mapping transform over self"… so when Int(String($0)) is nil, the result is discarded.

                        
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