swift - Swift 类型错误 :Cannot convert value of type '[UInt64]' to expected argument type 'inout UInt64'

Question

Swift 新手，我遇到了这个错误:

Cannot convert value of type '[UInt64]' to expected argument type 'inout UInt64'

我不明白“inout”打字

/// non crypto hash
func strHash(_ str: String) -> UInt64 {
    var result = UInt64 (5381)
    let buf = [UInt8](str.utf8)
    for b in buf {
        result = 127 * (result & 0x00ffffffffffffff) + UInt64(b)
    }
    return result
}

let myString: String = "Hello World"

let words = myString.components(separatedBy: " " )
print(words)
var hashArry = [UInt64]()
for w in words {
    hashArry += strHash(w) // <<<<<<<<< Here
}

Answer 1

嗯，您不能像您预期的那样使用 +=。 使用

hashArray.append(strHash(w))

相反。并且不要对有时非常困惑的编译器错误消息感到奇怪:-)