countUntil to print all the index of a given string.

[Cym13]

On Sunday, 18 February 2018 at 14:48:59 UTC, Cym13 wrote:
> [...]

Just thought of a much better/simpler solution for that last case 
that also doesn't force you to read all data (which might be 
impossible when dealing with infinite ranges):

     import std.range;
     import std.algorithm;

     a[]
      .enumerate                       // get tuples (index, value)
      .filter!(t => t[1] == "Test2")   // keep only if value == 
"Test2"
      .map!(t => t[0])                 // keep only the index part
      .writeln;

Completely lazy.