原文： https://yourbasic.org/golang/convert-string-to-byte-slice/#convert-string-to-bytes
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Basics
When you convert between a string and a byte slice (array), you get a brand new slice that contains the same bytes as the string, and vice versa.
- The conversion doesn’t change the data;
- the only difference is that strings are immutable, while byte slices can be modified.
If you need to manipulate the characters (runes) of a string, you may want to convert the string to a rune slice instead. See Convert between rune array/slice and string.
Convert string to bytes
When you convert a string to a byte slice, you get a new slice that contains the same bytes as the string.
b := []byte("ABC€")
fmt.Println(b) // [65 66 67 226 130 172]
Note that the character € is encoded in UTF-8 using 3 bytes. See the Go rune articlefor more on UTF-8 encoding of Unicode code points.
Convert bytes to string
When you convert a slice of bytes to a string, you get a new string that contains the same bytes as the slice.
s := string([]byte{65, 66, 67, 226, 130, 172})
fmt.Println(s) // ABC€
Performance
These conversions create a new slice or string, and therefore have time complexityproportional to the number of bytes that are processed.
More efficient alternative
In some cases, you might be able to use a string builder, which can concatenate strings without redundant copying: