• Alex (22/22) Jun 04 2016 Hi all!
• Alex (2/2) Jun 04 2016 PPS: The error shown is in line with the iota inside foreach:
• Brad Anderson (10/32) Jun 04 2016 Check out enumerate() in std.range;
• Brad Anderson (3/14) Jun 04 2016 How could I have forgotten the UFCS rox version...
• Alex (4/21) Jun 04 2016 :D

Alex <sascha.orlov gmail.com> writes:

Hi all!
Could you help me clearify why a iota can't be accessed with two 
arguments in a foreach loop?
following tests show my problem:
What does work:
     int[] ku = [0, 1, 2, 3, 4];
     foreach(i, el; ku)
         writeln("index: ", i, " element: ", el);
What does not work:
     counter = 5;
     foreach(i, el; iota(counter))
         writeln("index: ", i, " element: ", el);

Motivation: In real I want to have:
     counter = 5;
     foreach(i, el; randomCover(iota(counter)))
         writeln("index: ", i, " element: ", el);

so, I could follow a random permutation. Maybe there is another 
simple way to achieve this?

PS: needed imports:
     import std.random : randomCover;
     import std.range : iota;
     import std.stdio : writeln;

Alex <sascha.orlov gmail.com> writes:

PPS: The error shown is in line with the iota inside foreach:
Error: cannot infer argument types, expected 1 argument, not 2

Brad Anderson <eco gnuk.net> writes:

On Saturday, 4 June 2016 at 18:20:26 UTC, Alex wrote:
 Hi all!
 Could you help me clearify why a iota can't be accessed with 
 two arguments in a foreach loop?
 following tests show my problem:
 What does work:
     int[] ku = [0, 1, 2, 3, 4];
     foreach(i, el; ku)
         writeln("index: ", i, " element: ", el);
 What does not work:
     counter = 5;
     foreach(i, el; iota(counter))
         writeln("index: ", i, " element: ", el);

 Motivation: In real I want to have:
     counter = 5;
     foreach(i, el; randomCover(iota(counter)))
         writeln("index: ", i, " element: ", el);

 so, I could follow a random permutation. Maybe there is another 
 simple way to achieve this?

 PS: needed imports:
     import std.random : randomCover;
     import std.range : iota;
     import std.stdio : writeln;

Check out enumerate() in std.range;

     int counter = 5;
     foreach(i, el; enumerate(randomCover(iota(counter))))
         writeln("index: ", i, " element: ", el);

     index: 0 element: 3
     index: 1 element: 1
     index: 2 element: 0
     index: 3 element: 2
     index: 4 element: 4

Brad Anderson <eco gnuk.net> writes:

On Saturday, 4 June 2016 at 18:55:09 UTC, Brad Anderson wrote:
 On Saturday, 4 June 2016 at 18:20:26 UTC, Alex wrote:
     [...]

 Check out enumerate() in std.range;

     int counter = 5;
     foreach(i, el; enumerate(randomCover(iota(counter))))
         writeln("index: ", i, " element: ", el);

     index: 0 element: 3
     index: 1 element: 1
     index: 2 element: 0
     index: 3 element: 2
     index: 4 element: 4

How could I have forgotten the UFCS rox version...

foreach(i, el; iota(counter).randomCover.enumerate)

Alex <sascha.orlov gmail.com> writes:

On Saturday, 4 June 2016 at 18:58:51 UTC, Brad Anderson wrote:
 On Saturday, 4 June 2016 at 18:55:09 UTC, Brad Anderson wrote:
 On Saturday, 4 June 2016 at 18:20:26 UTC, Alex wrote:
     [...]

 Check out enumerate() in std.range;


Ah! thanks!

     int counter = 5;
     foreach(i, el; enumerate(randomCover(iota(counter))))
         writeln("index: ", i, " element: ", el);

     index: 0 element: 3
     index: 1 element: 1
     index: 2 element: 0
     index: 3 element: 2
     index: 4 element: 4

 How could I have forgotten the UFCS rox version...

:D

 foreach(i, el; iota(counter).randomCover.enumerate)

Thanks!