Merge pull request matplotlib#28599 from QuLogic/pyupgrade

Upgrade code to Python 3.10

Author: ksunden

galleries/examples/showcase/stock_prices.py

@@ -42,7 +42,7 @@
                  'ADBE', 'GSPC', 'IXIC']
 
 # Manually adjust the label positions vertically (units are points = 1/72 inch)
-y_offsets = {k: 0 for k in stocks_ticker}
+y_offsets = dict.fromkeys(stocks_ticker, 0)
 y_offsets['IBM'] = 5
 y_offsets['AAPL'] = -5
 y_offsets['AMZN'] = -6

galleries/examples/units/basic_units.py

@@ -7,6 +7,7 @@
 
 """
 
+import itertools
 import math
 
 from packaging.version import parse as parse_version
@@ -254,7 +255,7 @@ def get_unit(self):
 
 class UnitResolver:
     def addition_rule(self, units):
-        for unit_1, unit_2 in zip(units[:-1], units[1:]):
+        for unit_1, unit_2 in itertools.pairwise(units):
             if unit_1 != unit_2:
                 return NotImplemented
         return units[0]

lib/matplotlib/_api/__init__.pyi

@@ -1,5 +1,5 @@
-from collections.abc import Callable, Generator, Mapping, Sequence
-from typing import Any, Iterable, TypeVar, overload
+from collections.abc import Callable, Generator, Iterable, Mapping, Sequence
+from typing import Any, TypeVar, overload
 from typing_extensions import Self  # < Py 3.11
 
 from numpy.typing import NDArray

lib/matplotlib/_docstring.py

@@ -82,8 +82,8 @@ def __missing__(self, key):
         name = key[:-len(":kwdoc")]
         from matplotlib.artist import Artist, kwdoc
         try:
-            cls, = [cls for cls in _api.recursive_subclasses(Artist)
-                    if cls.__name__ == name]
+            cls, = (cls for cls in _api.recursive_subclasses(Artist)
+                    if cls.__name__ == name)
         except ValueError as e:
             raise KeyError(key) from e
         return self.setdefault(key, kwdoc(cls))

lib/matplotlib/_docstring.pyi

@@ -1,4 +1,5 @@
-from typing import Any, Callable, TypeVar, overload
+from collections.abc import Callable
+from typing import Any, TypeVar, overload
 
 
 _T = TypeVar('_T')

lib/matplotlib/_mathtext.py

@@ -376,7 +376,7 @@ def _get_info(self, fontname: str, font_class: str, sym: str, fontsize: float,
         font.set_size(fontsize, dpi)
         glyph = font.load_char(num, flags=self.load_glyph_flags)
 
-        xmin, ymin, xmax, ymax = [val/64.0 for val in glyph.bbox]
+        xmin, ymin, xmax, ymax = (val / 64 for val in glyph.bbox)
         offset = self._get_offset(font, glyph, fontsize, dpi)
         metrics = FontMetrics(
             advance=glyph.linearHoriAdvance / 65536,
@@ -2645,7 +2645,7 @@ def _genfrac(self, ldelim: str, rdelim: str, rule: float | None, style: _MathSty
             if rdelim == '':
                 rdelim = '.'
             return self._auto_sized_delimiter(ldelim,
-                                              T.cast(list[T.Union[Box, Char, str]],
+                                              T.cast(list[Box | Char | str],
                                                      result),
                                               rdelim)
         return result
@@ -2786,7 +2786,7 @@ def _auto_sized_delimiter(self, front: str,
                     del middle[idx]
             # There should only be \middle and its delimiter as str, which have
             # just been removed.
-            middle_part = T.cast(list[T.Union[Box, Char]], middle)
+            middle_part = T.cast(list[Box | Char], middle)
         else:
             height = 0
             depth = 0

lib/matplotlib/_mathtext_data.py

@@ -3,7 +3,7 @@
 """
 
 from __future__ import annotations
-from typing import overload, Union
+from typing import overload
 
 latex_to_bakoma = {
     '\\__sqrt__'                 : ('cmex10', 0x70),
@@ -1113,11 +1113,10 @@
 # Each element is a 4-tuple of the form:
 #   src_start, src_end, dst_font, dst_start
 
-_EntryTypeIn = tuple[str, str, str, Union[str, int]]
+_EntryTypeIn = tuple[str, str, str, str | int]
 _EntryTypeOut = tuple[int, int, str, int]
 
-_stix_virtual_fonts: dict[str, Union[dict[
-    str, list[_EntryTypeIn]], list[_EntryTypeIn]]] = {
+_stix_virtual_fonts: dict[str, dict[str, list[_EntryTypeIn]] | list[_EntryTypeIn]] = {
     'bb': {
         "rm": [
             ("\N{DIGIT ZERO}",
@@ -1729,8 +1728,7 @@ def _normalize_stix_fontcodes(d):
         return {k: _normalize_stix_fontcodes(v) for k, v in d.items()}
 
 
-stix_virtual_fonts: dict[str, Union[dict[str, list[_EntryTypeOut]],
-                                    list[_EntryTypeOut]]]
+stix_virtual_fonts: dict[str, dict[str, list[_EntryTypeOut]] | list[_EntryTypeOut]]
 stix_virtual_fonts = _normalize_stix_fontcodes(_stix_virtual_fonts)
 
 # Free redundant list now that it has been normalized

lib/matplotlib/animation.py

@@ -1086,8 +1086,8 @@ def _pre_composite_to_white(color):
         # canvas._is_saving = True makes the draw_event animation-starting
         # callback a no-op; canvas.manager = None prevents resizing the GUI
         # widget (both are likewise done in savefig()).
-        with writer.saving(self._fig, filename, dpi), \
-             cbook._setattr_cm(self._fig.canvas, _is_saving=True, manager=None):
+        with (writer.saving(self._fig, filename, dpi),
+              cbook._setattr_cm(self._fig.canvas, _is_saving=True, manager=None)):
             for anim in all_anim:
                 anim._init_draw()  # Clear the initial frame
             frame_number = 0

lib/matplotlib/artist.py

@@ -1,10 +1,11 @@
 from collections import namedtuple
 import contextlib
-from functools import cache, wraps
+from functools import cache, reduce, wraps
 import inspect
 from inspect import Signature, Parameter
 import logging
 from numbers import Number, Real
+import operator
 import re
 import warnings
 
@@ -1290,7 +1291,8 @@ def matchfunc(x):
             raise ValueError('match must be None, a matplotlib.artist.Artist '
                              'subclass, or a callable')
 
-        artists = sum([c.findobj(matchfunc) for c in self.get_children()], [])
+        artists = reduce(operator.iadd,
+                         [c.findobj(matchfunc) for c in self.get_children()], [])
         if include_self and matchfunc(self):
             artists.append(self)
         return artists

lib/matplotlib/axes/_axes.py

@@ -6000,7 +6000,7 @@ def _pcolorargs(self, funcname, *args, shading='auto', **kwargs):
             # unit conversion allows e.g. datetime objects as axis values
             X, Y = args[:2]
             X, Y = self._process_unit_info([("x", X), ("y", Y)], kwargs)
-            X, Y = [cbook.safe_masked_invalid(a, copy=True) for a in [X, Y]]
+            X, Y = (cbook.safe_masked_invalid(a, copy=True) for a in [X, Y])
 
             if funcname == 'pcolormesh':
                 if np.ma.is_masked(X) or np.ma.is_masked(Y):