• Murilo (3/3) Dec 27 2018 Why is it that when I type "auto choice = randomSample(array);"
• =?UTF-8?Q?Ali_=c3=87ehreli?= (20/22) Dec 27 2018 message?
• Murilo (2/6) Dec 28 2018 Thank you very much, now it all makes sense.

Murilo <murilomiranda92 hotmail.com> writes:

Why is it that when I type "auto choice = randomSample(array);" 
and later when I try to index choice as in choice[1] it gives an 
error message?

=?UTF-8?Q?Ali_=c3=87ehreli?= <acehreli yahoo.com> writes:

On 12/27/2018 06:06 PM, Murilo wrote:
 Why is it that when I type "auto choice = randomSample(array);" and
 later when I try to index choice as in choice[1] it gives an error 

message?

It's because randomSample returns either an input range or a forward 
range depending both on the kind of range that it gets and the random 
number generator used. Documented here:

   https://dlang.org/library/std/random/random_sample.html

Because it never returns a random access range, it does not provide 
indexing with operator []. If you definitely want random access, the 
normal thing to do is to copy the elements into an array with e.g. 
std.array.array (imported publicly by std.random):

import std.stdio;
import std.random;
import std.range;

void main() {
     auto array = 100.iota;
     // .array at the end returns an array:
     auto choice = randomSample(array, 10).array;
     writeln(choice[1]);
}

Ali

Murilo <murilomiranda92 hotmail.com> writes:

On Friday, 28 December 2018 at 03:59:52 UTC, Ali Çehreli wrote:
 It's because randomSample returns either an input range or a 
 forward range depending both on the kind of range that it gets 
 and the random number generator used. Documented here:
 Ali

Thank you very much, now it all makes sense.