英文:
Creating a byte slice with a known text string, in Golang
问题
我有这段文本，我想将其放入一个字节切片中：
s := "There are these two young fish swimming along and they happen to meet an older fish swimming the other way"
如果我写成：
b := []byte("There are these two young fish swimming along and they happen to meet an older fish swimming the other way")
据我了解，在运行时，这将会：
- 创建一个存储在内存中的字符串
- 创建一个字节切片
- 将字符串的内容复制到字节切片中（根据需要重新分配内存）
我可以将每个字符串值转换为它们的ASCII等效值，并直接创建字节切片：
b := []byte{84, 104, ... }
尽管这种方式不太易读。
我了解到这个例子有点琐碎，大多数计算机可以立即完成这个操作，但我对此很好奇。编译器是否会解释[]byte("blah")并在编译时将其转换为高效的字节切片？如果字符串包含非ASCII字符，最佳解决方案是否会改变？
英文:
I have this text which I would like to put into a byte slice:
s := "There are these two young fish swimming along and they happen to meet an older fish swimming the other way"
If I write
b := []byte("There are these two young fish swimming along and they happen to meet an older fish swimming the other way")
As I understand, at runtime this will:
- create a string with the values in memory
- create a byte slice
- copy the contents of the string into the byte slice (reallocating as necessary)
I could convert each of the string values to their ASCII equivalent and create the byte slice directly:
b := []byte{84, 104, ... }
though this isn't very readable.
I understand that the example here is a little trivial and most computers can do this in a flash, but I'm curious about it. Does the compiler interpret []byte("blah") and turn it into an efficient byte slice at compile time? Would the best solution change if the string included non-ASCII characters?
答案1
得分: 5
Go将字符串作为字符串字面量嵌入可执行程序中。它使用runtime.stringtoslicebyte函数在运行时将字符串字面量转换为字节切片。
英文:
Go embeds the string in the executable program as a string literal. It converts the string literal to a byte slice at runtime using the runtime.stringtoslicebyte function.
答案2
得分: 4
如果你从一个常量字符串初始化一个[]byte变量，编译器似乎足够聪明，不会创建一个中间字符串：相反，字节切片的支持数组直接从静态数据初始化，而不是首先构造一个字符串变量。
虽然存在数据复制，但这在构造可变类型时是可以预期的。
英文:
If you are initialising a []byte variable from a constant string, it looks like the compiler is smart enough not to create an intermediate string: instead, the backing array for the byte slice is initialised directly from static data rather than constructing a string variable first.
There is a data copy, but that is to be expected when constructing a mutable type.
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