convert string to ubyte[]

[Mike Parker]

On Saturday, 11 November 2017 at 15:38:18 UTC, aki wrote:
> Hello,
>
> This will be trivial question but I cannot figure out
> what's wrong. I want to convert string to an array of ubyte.
>
> import std.conv;
> void main() {
>         auto s = "hello";
>         ubyte[] b = to!(ubyte[])(s);
> }
>
> It compiles but cause run time error:
>
> std.conv.ConvException at C:\APP\D\dmd2\windows\bin\..\..\src\phobos\std\conv.d(3530): Can't parse string: "[" is missing
>
> I cannot understand the meaning of this message.
> Replacing s with s.dup to remove immutable doesn't help.
> Do I need to use cast?
>
> Regards,
> Aki

I don't know about the error you're seeing, but the generic way 
to get an array of the underlying data type of a string is via 
std.string.representation.

import std.string;
auto s = "hello";
auto bytes = s.representation;

https://dlang.org/phobos/std_string.html#.representation

You can also simply cast to the appropriate type if you already 
know what type of string you have.

auto bytes = cast(immutable(ubyte)[])s;

Of course, if you need a mutable array you should dup:

auto bytes = cast(ubyte[])s.dup;