Swift将字符的出现计数为字符串
示例
给定aString和aCharacter
let text = "Hello World" let char: Character = "o"
我们可以计算出Character出现在String使用中的次数
let sensitiveCount = text.characters.filter { $0 == char }.count //区分大小写
let insensitiveCount = text.lowercaseString.characters.filter { $0 == Character(String(char).lowercaseString) } //不区分大小写