如何在Swift中使用uppercaseString,lowercaseString

Question

我有Strings,我想转换为uppercaseString,lowercaseString与only letters.

我的琴弦;

let uppers  = " Hello*im ; + Upper+String "
let lowers  = " Hello*im ; + Lower+String "
print(uppers)
print(lowers)

大写的输出看起来像这样

HELLOIMUPPERSTRING 

谢谢 !

Answer 1

你可以用Set它.

let uppers  = " Hello*im ; + Upper+String "
let lowers  = " Hello*im ; + Lower+String "
let allowChars : Set<Character> = Set("abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLKMNOPQRSTUVWXYZ1234567890".characters)
let upperStr = String(uppers.characters.filter {allowChars.contains($0) }).uppercaseString
let lowerStr = String(lowers.characters.filter {allowChars.contains($0) }).lowercaseString
print(upperStr)
print(lowerStr)

编辑:要允许空格,还要在Set字符内添加其他字符的空格

let allowChars : Set<Character> = Set("abcdefghijklmnopqrstuvwxyz ABCDEFGHIJKLKMNOPQRSTUVWXYZ1234567890".characters)