Sort by confidence and remove excess boxes without explicit if (#10517)

* sort by confidence and remove excess boxes without explicit if

Signed-off-by: Yonghye Kwon <developer.0hye@gmail.com>

* cleanup indexing boxes for remove excess boxes

it is related to https://github.com/ultralytics/yolov5/pull/10502.

Signed-off-by: Yonghye Kwon <developer.0hye@gmail.com>
Co-authored-by: Glenn Jocher <glenn.jocher@ultralytics.com>

utils/general.py

@@ -969,10 +969,7 @@ def non_max_suppression(
         n = x.shape[0]  # number of boxes
         if not n:  # no boxes
             continue
-        elif n > max_nms:  # excess boxes
-            x = x[x[:, 4].argsort(descending=True)[:max_nms]]  # sort by confidence
-        else:
-            x = x[x[:, 4].argsort(descending=True)]  # sort by confidence
+        x = x[x[:, 4].argsort(descending=True)[:max_nms]]  # sort by confidence and remove excess boxes
 
         # Batched NMS
         c = x[:, 5:6] * (0 if agnostic else max_wh)  # classes