摘要:
updateValue(_:forKey:)Inserts or updates a value for a given key and returns the previous value for that key if one existed, ornilif a previous value ... 阅读全文
摘要:
if let actualNumber = possibleNumber.toInt(){ //如果possibleNumber.toInt是一个整形赋值给actualNumber,并打印 true 分支 println("\(possibleNumber) has an integer valu... 阅读全文