Error: variable i cannot be read at compile time

[Vino]

On Saturday, 6 January 2018 at 06:47:33 UTC, Vino wrote:
> On Friday, 5 January 2018 at 18:00:34 UTC, thedeemon wrote:
>> On Friday, 5 January 2018 at 17:59:32 UTC, thedeemon wrote:
>>>     Tuple!( staticMap!(Arr, ColumnTypes) ) res; // array of 
>>> tuples
>>
>> Sorry, I meant tuple of arrays, of course.
>
> Hi Deemon,
>
>  Thank you very much, I tested your code, initially the code 
> did not produce the expected output, and found an issue in the 
> the key line of code as below, after updating the output was as 
> expected. Can you please let me know how to change the array 
> from standard array to container array.
>
> auto ks = col.map!(v => col.countUntil(v)).array; // Your 
> code(col.countUntil)
> auto ks = col.map!(v => vals.countUntil(v)).array; // Changed 
> code(vals.countUntil)
>
> From,
> Vino.B

Hi Deemon,

Was able to convert 50% of the code to container array and facing 
some issue

import std.algorithm: countUntil, joiner, sort, uniq, map;
import std.csv: csvReader;
import std.stdio: File, writeln;
import std.typecons: Tuple, tuple;
import std.meta: AliasSeq;
import std.container.array;

alias ColumnTypes = AliasSeq!(string, string, int);
alias Arr(T) = Array!T;

auto readData() {
auto file = 
File("C:\\Users\\bheev1\\Desktop\\Current\\Script\\Others\\TColRead.csv", "r");
Arr!(Tuple!ColumnTypes) res;
foreach (record; 
file.byLineCopy.joiner("\n").csvReader!(Tuple!ColumnTypes))
	{ res.insertBack(record); }	
return tuple(res[]);   // replace this line with writeln(res[]); 
gives the expected output
}

auto compress(T)(Array!T col) {
	Arr!int ks; Array!T vals;
     vals.insertBack(sort(col.dup[]).uniq);
	ks.insertBack(col.map!(v => vals.countUntil(v)));
	return tuple(vals, ks);
}

void main() {
    auto columns = readData();
    foreach(i, ColT; ColumnTypes) {               //Facing some 
issue at this point
		auto vk = compress(columns[i]);
		writeln(vk[0][], vk[1][]);
	}
}


From,
Vino.B