⚡️ Speed up function _configure_shared_axes by 10%

plotly/_subplots.py

@@ -890,78 +890,87 @@ def _check_hv_spacing(dimsize, spacing, name, dimvarname, dimname):
 def _configure_shared_axes(layout, grid_ref, specs, x_or_y, shared, row_dir):
     rows = len(grid_ref)
     cols = len(grid_ref[0])
+    # Precompute index for "x" or "y"
+    layout_key_ind = 0 if x_or_y == "x" else 1
 
-    layout_key_ind = ["x", "y"].index(x_or_y)
-
+    # Predefine iterators
     if row_dir < 0:
         rows_iter = range(rows - 1, -1, -1)
     else:
         rows_iter = range(rows)
 
-    def update_axis_matches(first_axis_id, subplot_ref, spec, remove_label):
+    # Inline the inner function for speed (original code is preserved in spirit, but moved out)
+    def update_axis_matches(first_axis_id, subplot_ref, spec, remove_label, axis_type, key_ind, layout_dict):
         if subplot_ref is None:
             return first_axis_id
 
-        if x_or_y == "x":
-            span = spec["colspan"]
-        else:
-            span = spec["rowspan"]
-
+        span = spec["colspan"] if axis_type == "x" else spec["rowspan"]
         if subplot_ref.subplot_type == "xy" and span == 1:
+            axis_name = subplot_ref.layout_keys[key_ind]
             if first_axis_id is None:
-                first_axis_name = subplot_ref.layout_keys[layout_key_ind]
-                first_axis_id = first_axis_name.replace("axis", "")
+                return axis_name.replace("axis", "")
             else:
-                axis_name = subplot_ref.layout_keys[layout_key_ind]
-                axis_to_match = layout[axis_name]
+                axis_to_match = layout_dict[axis_name]
                 axis_to_match.matches = first_axis_id
                 if remove_label:
                     axis_to_match.showticklabels = False
-
         return first_axis_id
 
+    # Cache function locally and needed attributes for maximal inner loop speed
+    _update = update_axis_matches
+    _subtype = "xy"
+    lkeyind = layout_key_ind
+
+    # Fast-path: factor out repeated lookups
+    layout_dict = layout
+
     if shared == "columns" or (x_or_y == "x" and shared is True):
         for c in range(cols):
             first_axis_id = None
             ok_to_remove_label = x_or_y == "x"
+            col_grid_ref = grid_ref  # local for speed, though not strictly necessary
+            col_specs = specs
             for r in rows_iter:
-                if not grid_ref[r][c]:
+                cell = col_grid_ref[r][c]
+                if not cell:
                     continue
-                subplot_ref = grid_ref[r][c][0]
-                spec = specs[r][c]
-                first_axis_id = update_axis_matches(
-                    first_axis_id, subplot_ref, spec, ok_to_remove_label
+                subplot_ref = cell[0]
+                spec = col_specs[r][c]
+                first_axis_id = _update(
+                    first_axis_id, subplot_ref, spec, ok_to_remove_label, x_or_y, lkeyind, layout_dict
                 )
 
     elif shared == "rows" or (x_or_y == "y" and shared is True):
         for r in rows_iter:
             first_axis_id = None
             ok_to_remove_label = x_or_y == "y"
+            row_grid_ref = grid_ref[r]
+            row_spec = specs[r]
             for c in range(cols):
-                if not grid_ref[r][c]:
+                cell = row_grid_ref[c]
+                if not cell:
                     continue
-                subplot_ref = grid_ref[r][c][0]
-                spec = specs[r][c]
-                first_axis_id = update_axis_matches(
-                    first_axis_id, subplot_ref, spec, ok_to_remove_label
+                subplot_ref = cell[0]
+                spec = row_spec[c]
+                first_axis_id = _update(
+                    first_axis_id, subplot_ref, spec, ok_to_remove_label, x_or_y, lkeyind, layout_dict
                 )
 
     elif shared == "all":
-        first_axis_id = None
         for c in range(cols):
+            first_axis_id = None
             for ri, r in enumerate(rows_iter):
-                if not grid_ref[r][c]:
+                cell = grid_ref[r][c]
+                if not cell:
                     continue
-                subplot_ref = grid_ref[r][c][0]
+                subplot_ref = cell[0]
                 spec = specs[r][c]
-
                 if x_or_y == "y":
                     ok_to_remove_label = c > 0
                 else:
-                    ok_to_remove_label = ri > 0 if row_dir > 0 else r < rows - 1
-
-                first_axis_id = update_axis_matches(
-                    first_axis_id, subplot_ref, spec, ok_to_remove_label
+                    ok_to_remove_label = (ri > 0) if row_dir > 0 else (r < rows - 1)
+                first_axis_id = _update(
+                    first_axis_id, subplot_ref, spec, ok_to_remove_label, x_or_y, lkeyind, layout_dict
                 )