parenthesis and curly braces difference in golang

user_150365 0
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a := []byte("H") //works
a := []byte{"H"} //does not compile

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

go
2 Answers

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
user_2441280

In the first one a := []byte("H") you are type casting the string "H" into a byte array.

In the second one a := []byte{"H"} you are defining a byte array and assigning "H" as it's first value, which is invalid.

You can compare the second one with defining a string array:

s := []string{"hello","world",".."} // works
f := []string{1,2,4} // fails because the datatype is wrong
user_5602990
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