How to assign string to bytes array

Question

I want to assign string to bytes array   var arr  20 byte str     abc  for k  v    range   byte str      arr k    byte v      Have another method

User · Answer

Ended up creating array specific methods to do this. Much like the encoding/binary package with specific methods for each int type. For example binary.BigEndian.PutUint16([]byte, uint16).

func byte16PutString(s string) [16]byte {
    var a [16]byte
    if len(s) > 16 {
        copy(a[:], s)
    } else {
        copy(a[16-len(s):], s)
    }
    return a
}

var b [16]byte
b = byte16PutString("abc")
fmt.Printf("%v\n", b)

Output:

[0 0 0 0 0 0 0 0 0 0 0 0 0 97 98 99]

Notice how I wanted padding on the left, not the right.

http://play.golang.org/p/7tNumnJaiN

User · Answer

Piece of cake   arr      byte  That s all folks

User · Answer

Arrays are values    slices are more like pointers  That is  n type is not compatible with   type as they are fundamentally two different things  You can get a slice that points to an array by using arr    which returns a slice that has arr as it s backing storage    One way to convert a slice of for example   byte to  20 byte is to actually allocate a  20 byte which you can do by using var  20 byte  as it s a value    no make needed  and then copy data into it   buf    make   byte  10  var arr  10 byte copy arr     buf    Essentially what a lot of other answers get wrong is that   type is NOT an array     n T and   T are completely different things   When using reflect   T is not of kind Array but of kind Slice and  n T is of kind Array    You also can t use map   byte T but you can use map  n byte T    This can sometimes be cumbersome because a lot of functions operate for example on   byte whereas some functions return  n byte  most notably the hash functions in crypto      A sha256 hash for example is  32 byte and not   byte so when beginners try to write it to a file for example   sum    sha256 Sum256 data  w Write sum    they will get an error  The correct way of is to use  w Write sum       However  what is it that you want  Just accessing the string bytewise  You can easily convert a string to   byte using   bytes      byte str    but this isn t an array  it s a slice  Also  byte    rune  In case you want to operate on  characters  you need to use rune    not byte

User · Answer

For example   package main  import  fmt   func main         s     abc      var a  20 byte     copy a     s      fmt Println  s      byte s    a    a      Output   s   97 98 99  a   97 98 99 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

User · Answer

I think it s better    package main  import  fmt   func main         str     abc      mySlice      byte str      fmt Printf   v - gt    s   mySlice mySlice       Check here  http   play golang org p vpnAWHZZk7

User · Answer

Go  convert a string to a bytes slice  You need a fast way to convert a   string to   byte type  To use in situations such as storing text data into a random access file or other type of data manipulation that requires the input data to be in   byte type   package main  func main          var s string                 b      byte s                 which is useful when using ioutil WriteFile  which accepts a bytes slice as its data parameter   WriteFile func filename string  data   byte  perm os FileMode  error   Another example  package main  import        fmt       strings     func main          stringSlice      string  hello    world        stringByte    strings Join stringSlice               Byte array value     fmt Println   byte stringByte           Corresponding string value     fmt Println string   byte stringByte        Output       104 101 108 108 111 32 119 111 114 108 100  hello world   Please check the link playground

User · Answer

Besides the methods mentioned above  you can also do a trick as  s     hello  b         byte  unsafe Pointer   reflect SliceHeader  unsafe Pointer  amp s       Go Play  http   play golang org p xASsiSpQmC  You should never use this  -

User · Answer

For converting from a string to a byte slice  string - gt    byte     byte str    For converting an array to a slice   20 byte - gt    byte   arr      For copying a string to an array  string - gt   20 byte   copy arr     str    Same as above  but explicitly converting the string to a slice first   copy arr       byte str        The built-in copy function only copies to a slice  from a slice  Arrays are  the underlying data   while slices are  a viewport into underlying data   Using     makes an array qualify as a slice  A string does not qualify as a slice that can be copied to  but it qualifies as a slice that can be copied from  strings are immutable   If the string is too long  copy will only copy the part of the string that fits      This code   var arr  20 byte copy arr      abc   fmt Printf  array   v   T  n   arr  arr       gives the following output   array   97 98 99 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0    20 uint8    I also made it available at the Go Playground

User · Answer

Safe and simple     byte  Here is a string

[go] How to assign string to bytes array

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