将字符串转换为采用UTF-8编码的数据会失败吗?

问题描述：

为了在Swift中将String实例转换为Data实例，您可以使用data(using:allowLossyConversion:)，它返回一个可选的Data实例.

In order to convert a String instance to a Data instance in Swift you can use data(using:allowLossyConversion:), which returns an optional Data instance.

如果编码为UTF-8(String.Encoding.utf8)，此函数的返回值是否可以为nil?

Can the return value of this function ever be nil if the encoding is UTF-8 (String.Encoding.utf8)?

如果返回值不能为nil，则始终强制展开此类转换是安全的.

If the return value cannot be nil it would be safe to always force-unwrap such a conversion.

答

UTF-8可以表示所有有效的Unicode代码点，因此需要进行转换 Swift字符串转换为UTF-8数据不会失败.

UTF-8 can represent all valid Unicode code points, therefore a conversion of a Swift string to UTF-8 data cannot fail.

强行打开

let string = "some string .."
let data = string.data(using: .utf8)!

很安全.

对于.utf16或.utf32同样如此，但对于仅代表受限字符集的编码，例如.ascii或.isoLatin1.

The same would be true for .utf16 or .utf32, but not for encodings which represent only a restricted character set, such as .ascii or .isoLatin1.

您也可以使用字符串的.utf8视图创建UTF-8数据，避免强行打开包装:

You can alternatively use the .utf8 view of a string to create UTF-8 data, avoiding the forced unwrap:

let string = "some string .."
let data = Data(string.utf8)

将字符串转换为采用UTF-8编码的数据会失败吗?

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