perf: use np.sum to compute sum (#122)

Author: maldil

pdftotree/utils/pdf/pdf_parsers.py

@@ -13,6 +13,7 @@
 from functools import cmp_to_key
 from typing import Any, Dict, List, Tuple
 
+import numpy as np
 from pdfminer.layout import LTFigure, LTTextLine
 from pdfminer.utils import Plane
 
@@ -1274,11 +1275,8 @@ def get_page_width(boxes):
 
 
 def get_char_width(boxes: List[LTTextLine]) -> float:
-    box_len_sum = 0
-    num_char_sum = 0
-    for i, b in enumerate(boxes):
-        box_len_sum = box_len_sum + b.bbox[2] - b.bbox[0]
-        num_char_sum = num_char_sum + len(b.get_text())
+    box_len_sum = np.sum([b.bbox[2] - b.bbox[0] for b in boxes])
+    num_char_sum = np.sum([len(b.get_text()) for b in boxes])
     try:
         return box_len_sum / num_char_sum
     except ZeroDivisionError: