RebarsFilteringAfterCropping.cs

rebars
  .Select((rebar, rebarIndex) => linesAfterCropping.ElementAt(rebarIndex)
      .Select(lines =>
      {
          var shapeCode = rebar.ShapeCode;
          if (shapeCode == ShapeCodes.ANGULAR || shapeCode == ShapeCodes.G_LIKE)
          {
              if (lines.Count == 1) return new Rebar(rebar, lines) { ShapeCode = ShapeCodes.LINE };
              return new Rebar(rebar, lines);
          }
          if (shapeCode == ShapeCodes.TRANS_VERSE)
          {
              return SU.Equals(rebar.Polyline.First().Length, lines.First().Length) ? rebar : null;
          }
          if (shapeCode == ShapeCodes.P_LIKE)
          {
              return lines.Count == 3 ? new Rebar(rebar, lines) : null;
          }

          return new Rebar(rebar, lines);
      })
      .Where(r => r != null)
  )
  .SelectMany(s => s)
  .ToList();