gistfile1.txt

unit uEtl;

interface

uses
  Generics.Collections;

type
  IETL = interface
    function Transform(aOld: TDictionary<integer, TList<string>>): TDictionary<string, integer>;
  end;

  TETL = class(TInterfacedObject, IETL)
  private
    fDict: TDictionary<string, integer>;
  public
    constructor Create;
    destructor Destroy; override;
    function Transform(aOld: TDictionary<integer, TList<string>>): TDictionary<string, integer>;
  end;

function ETL: IETL;

implementation

function ETL: IETL;
begin
  Result := TETL.Create;
end;

constructor TETL.Create;
begin
  inherited;
  fDict := TDictionary<string, integer>.Create;
end;

destructor TETL.Destroy;
begin
  fDict.Free;
  inherited;
end;

function TETL.Transform(aOld: TDictionary<integer, TList<string>>): TDictionary<string, integer>;
var
  vPair: TPair<Integer, String>;
begin
  for vPair in aOld do
    fDict.Add(vPair.Value, vPair.Key);

  Result := fDict;
end;

end.