golang中括号和花括号的区别

Question

a := []byte("H") //works
a := []byte{"H"} //does not compile

What is the conceptual difference between () and {} as used above?

Answer 1

The reason is the difference between type conversions and slice literals.

_ = []byte("Hi!")         // Converts a string literal to a []byte.
_ = []byte{'H', 'i', '!'} // Initializes a []byte literal

Your second example []byte{"H"} fails to compile because "H" is a string literal that is being used in place of a rune literal, it's comparable to trying to assign a string to a byte typed variable:

var y byte = 'H' // OK
var x byte = "H" // ERROR: cannot use "H" (type string) as type byte in assignment