How to convert byte array to string in Go

Question

[]byte to string raises an error. string([]byte[:n]) raises an error too. By the way, for example, sha1 value to string for filename. Does it need utf-8 or any other encoding set explicitly? Thanks!

`[]byte` can be converted directly to `string`. Please show an example of what problem you're having. — JimB, Nov 16 '16 at 13:59
If you just show us an example of what you tried, it would be a very easy question to answer, rather than waiting for us to guess the correct answer. — JimB, Nov 17 '16 at 16:40
In most modern languages it would be perfectly clear what he was trying to do, sadly, and without any additional context needed. I also stumbled upon this question looking for the same answer (as answered below). — milosmns, Nov 03 '19 at 17:46
@JimB Byte arrays cannot be directly converted to a string. Only byte slices. — Rawley Fowler, Mar 06 '22 at 21:20

score 179 · Answer 1 · edited Aug 05 '20 at 04:34

179

The easiest method I use to convert byte to string is:

myString := string(myBytes[:])

edited Aug 05 '20 at 04:34

Pang

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answered Nov 18 '16 at 09:07

warbear0129

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Why the `:`? What's the difference between this answer and `myString := string(myBytes)`? – Ferran Maylinch Dec 14 '21 at 09:19
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The `:` is needed because byte *arrays* cannot be directly turned to a string while slices can. Let's say we have `var b [64]byte` . `string(b)` will fail while `string(b[:])` will work. – MKrup Jan 04 '22 at 16:26

score 104 · Answer 2 · answered Dec 04 '19 at 11:52

104

The easiest way to convert []byte to string in Go:

myString := string(myBytes)

Note: to convert a "sha1 value to string" like you're asking, it needs to be encoded first, since a hash is binary. The traditional encoding for SHA hashes is hex (import "encoding/hex"):

myString := hex.EncodeToString(sha1bytes)

answered Dec 04 '19 at 11:52

rustyx

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Does the string contain a copy of the bytes? – ceving Jun 11 '23 at 13:10
Yes, it contains an immutable copy of the bytes. – rustyx Jul 06 '23 at 08:21

score 16 · Answer 3 · edited Nov 16 '16 at 20:20

16

In Go you convert a byte array (utf-8) to a string by doing string(bytes) so in your example, it should be string(byte[:n]) assuming byte is a slice of bytes.

edited Nov 16 '16 at 20:20

Martin Tournoij

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answered Nov 16 '16 at 13:04

Franck Jeannin

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I have just try like this.but failed. In fact ,I need to convert a file sha1 value to string ,named for the filename – lindsay show Nov 17 '16 at 02:11

alarcl · Answer 4 · 2016-11-17T08:11:21.450

15

I am not sure that i understand question correctly, but may be:

var ab20 [20]byte = sha1.Sum([]byte("filename.txt"))
var sx16 string = fmt.Sprintf("%x", ab20)
fmt.Print(sx16)

https://play.golang.org/p/haChjjsH0-

edited Nov 17 '16 at 08:11

answered Nov 17 '16 at 08:03

alarcl

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While technically correct, it's rather unusual in Go to use `var` and declare every type without just inferring them. https://play.golang.org/p/JUl57LKfzk – JimB Nov 17 '16 at 16:39
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Ah! "%x"! That's what I was doing wrong! :) I was using the wrong Sprintf placeholder, duh... – Gwyneth Llewelyn Jun 04 '17 at 17:52
You could also use `hex.EncodeToString` instead of `fmt.Sprintf("%x", ...)`. – Olshansky Jan 06 '22 at 23:48

score 4 · Answer 5 · answered May 03 '20 at 13:49

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ToBe := [6]byte{65, 66, 67, 226, 130, 172}
s:=ToBe[:3]
// this will work
fmt.Printf("%s",string(s))
// this will not
fmt.Printf("%s",string(ToBe))

Difference : ToBe is an array whereas s is a slice.

answered May 03 '20 at 13:49

Dev Kalra

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score 1 · Answer 6 · edited May 23 '17 at 11:59

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First you're getting all these negatives reviews because you didn't provided any code. Second, without a good example. This is what i'd do

var Buf bytes.Buffer
Buf.Write([]byte)
myString := Buf.String()
Buf.Reset() // Reset the buffer to reuse later

or better yet

myString := string(someByteArray[:n])

see here also see @JimB's comment

That being said if you help that targets your program, please provide and example of what you've tried, the expect results, and error.

edited May 23 '17 at 11:59

Community

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answered Nov 16 '16 at 19:54

reticentroot

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Thanks a lot. EncodeToString returns the hexadecimal encoding of src.it works well. – lindsay show Nov 17 '16 at 04:34

score 0 · Answer 7 · answered Apr 02 '19 at 08:16

We can just guess what is wrong with your code because no meaningful example is provided. But first what I see that string([]byte[:n]) is not valid at all. []byte[:n] is not a valid expression because no memory allocated for the array. Since byte array could be converted to string directly I assume that you have just a syntax error.

Shortest valid is fmt.Println(string([]byte{'g', 'o'}))

How to convert byte array to string in Go

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