MNT: Update code with Python 3.9+ syntax

Command: `pyupgrade --py39-plus`

Manual updates to add some f-strings and ignore f-strings in tex
formats.

Author: greglucas

doc/conf.py

@@ -141,7 +141,7 @@ def _check_dependencies():
     if missing:
         raise ImportError(
             "The following dependencies are missing to build the "
-            "documentation: {}".format(", ".join(missing)))
+            f"documentation: {', '.join(missing)}")
     if shutil.which('dot') is None:
         raise OSError(
             "No binary named dot - graphviz must be installed to build the "

doc/sphinxext/gallery_order.py

@@ -114,7 +114,7 @@ def __init__(self, src_dir):
     def __call__(self, item):
         """Return a string determining the sort order."""
         if item in self.ordered_list:
-            return "{:04d}".format(self.ordered_list.index(item))
+            return f"{self.ordered_list.index(item):04d}"
         else:
             # ensure not explicitly listed items come last.
             return "zzz" + item

doc/sphinxext/missing_references.py

@@ -61,7 +61,7 @@ def record_missing_reference(app, record, node):
     target = node["reftarget"]
     location = get_location(node, app)
 
-    domain_type = "{}:{}".format(domain, typ)
+    domain_type = f"{domain}:{typ}"
 
     record[(domain_type, target)].add(location)
 

examples/color/color_cycle_default.py

@@ -30,7 +30,7 @@
 
     axs[1, icol].set_facecolor('k')
     axs[1, icol].xaxis.set_ticks(np.arange(0, 10, 2))
-    axs[0, icol].set_title('line widths (pts): %g, %g' % (lwx, lwy),
+    axs[0, icol].set_title(f'line widths (pts): {lwx:g}, {lwy:g}',
                            fontsize='medium')
 
 for irow in range(2):

examples/event_handling/cursor_demo.py

@@ -58,7 +58,7 @@ def on_mouse_move(self, event):
             # update the line positions
             self.horizontal_line.set_ydata(y)
             self.vertical_line.set_xdata(x)
-            self.text.set_text('x=%1.2f, y=%1.2f' % (x, y))
+            self.text.set_text(f'x={x:1.2f}, y={y:1.2f}')
             self.ax.figure.canvas.draw()
 
 
@@ -134,7 +134,7 @@ def on_mouse_move(self, event):
             x, y = event.xdata, event.ydata
             self.horizontal_line.set_ydata(y)
             self.vertical_line.set_xdata(x)
-            self.text.set_text('x=%1.2f, y=%1.2f' % (x, y))
+            self.text.set_text(f'x={x:1.2f}, y={y:1.2f}')
 
             self.ax.figure.canvas.restore_region(self.background)
             self.ax.draw_artist(self.horizontal_line)
@@ -206,7 +206,7 @@ def on_mouse_move(self, event):
             # update the line positions
             self.horizontal_line.set_ydata(y)
             self.vertical_line.set_xdata(x)
-            self.text.set_text('x=%1.2f, y=%1.2f' % (x, y))
+            self.text.set_text(f'x={x:1.2f}, y={y:1.2f}')
             self.ax.figure.canvas.draw()
 
 

examples/event_handling/pick_event_demo2.py

@@ -43,7 +43,7 @@ def onpick(event):
     figi, axs = plt.subplots(N, squeeze=False)
     for ax, dataind in zip(axs.flat, event.ind):
         ax.plot(X[dataind])
-        ax.text(.05, .9, 'mu=%1.3f\nsigma=%1.3f' % (xs[dataind], ys[dataind]),
+        ax.text(.05, .9, f'mu={xs[dataind]:1.3f}\nsigma={ys[dataind]:1.3f}',
                 transform=ax.transAxes, va='top')
         ax.set_ylim(-0.5, 1.5)
     figi.show()

examples/lines_bars_and_markers/bar_label_demo.py

@@ -80,7 +80,7 @@
 ax.set_title('How fast do you want to go today?')
 
 # Label with given captions, custom padding and annotate options
-ax.bar_label(hbars, labels=['±%.2f' % e for e in error],
+ax.bar_label(hbars, labels=[f'±{e:.2f}' for e in error],
              padding=8, color='b', fontsize=14)
 ax.set_xlim(right=16)
 
@@ -106,9 +106,7 @@
 fig, ax = plt.subplots()
 bar_container = ax.bar(animal_names, mph_speed)
 ax.set(ylabel='speed in MPH', title='Running speeds', ylim=(0, 80))
-ax.bar_label(
-    bar_container, fmt=lambda x: '{:.1f} km/h'.format(x * 1.61)
-)
+ax.bar_label(bar_container, fmt=lambda x: f'{x * 1.61:.1f} km/h')
 
 # %%
 #

examples/scales/symlog_demo.py

@@ -1,4 +1,3 @@
-
 """
 ===========
 Symlog Demo

examples/shapes_and_collections/donut.py

@@ -53,7 +53,7 @@ def make_circle(r):
     patch = mpatches.PathPatch(path, facecolor='#885500', edgecolor='black')
     ax.add_patch(patch)
 
-    ax.annotate("Outside %s,\nInside %s" % (wise(outside), wise(inside)),
+    ax.annotate(f"Outside {wise(outside)},\nInside {wise(inside)}",
                 (i * 2.5, -1.5), va="top", ha="center")
 
 ax.set_xlim(-2, 10)

examples/user_interfaces/toolmanager_sgskip.py

@@ -37,7 +37,7 @@ def trigger(self, *args, **kwargs):
             keys = ', '.join(sorted(self.toolmanager.get_tool_keymap(name)))
             print(fmt_tool(name, tools[name].description, keys))
         print('_' * 80)
-        fmt_active_toggle = "{0!s:12} {1!s:45}".format
+        fmt_active_toggle = "{!s:12} {!s:45}".format
         print("Active Toggle tools")
         print(fmt_active_toggle("Group", "Active"))
         print('-' * 80)

lib/matplotlib/__init__.py

@@ -231,7 +231,7 @@ def _check_versions():
 
 # The decorator ensures this always returns the same handler (and it is only
 # attached once).
-@functools.lru_cache()
+@functools.lru_cache
 def _ensure_handler():
     """
     The first time this function is called, attach a `StreamHandler` using the
@@ -321,7 +321,7 @@ class ExecutableNotFoundError(FileNotFoundError):
     pass
 
 
-@functools.lru_cache()
+@functools.lru_cache
 def _get_executable_info(name):
     """
     Get the version of some executable that Matplotlib optionally depends on.
@@ -364,7 +364,7 @@ def impl(args, regex, min_ver=None, ignore_exit_code=False):
         try:
             output = subprocess.check_output(
                 args, stderr=subprocess.STDOUT,
-                universal_newlines=True, errors="replace")
+                text=True, errors="replace")
         except subprocess.CalledProcessError as _cpe:
             if ignore_exit_code:
                 output = _cpe.output
@@ -459,7 +459,7 @@ def impl(args, regex, min_ver=None, ignore_exit_code=False):
                 f"version supported by Matplotlib is 3.0")
         return info
     else:
-        raise ValueError("Unknown executable: {!r}".format(name))
+        raise ValueError(f"Unknown executable: {name!r}")
 
 
 @_api.deprecated("3.6", alternative="a vendored copy of this function")
@@ -757,7 +757,7 @@ def __repr__(self):
             repr_split = pprint.pformat(dict(self), indent=1,
                                         width=80 - indent).split('\n')
         repr_indented = ('\n' + ' ' * indent).join(repr_split)
-        return '{}({})'.format(class_name, repr_indented)
+        return f'{class_name}({repr_indented})'
 
     def __str__(self):
         return '\n'.join(map('{0[0]}: {0[1]}'.format, sorted(self.items())))
@@ -799,7 +799,7 @@ def rc_params(fail_on_error=False):
     return rc_params_from_file(matplotlib_fname(), fail_on_error)
 
 
-@functools.lru_cache()
+@functools.lru_cache
 def _get_ssl_context():
     try:
         import certifi
@@ -1041,7 +1041,7 @@ def rc(group, **kwargs):
     for g in group:
         for k, v in kwargs.items():
             name = aliases.get(k) or k
-            key = '%s.%s' % (g, name)
+            key = f'{g}.{name}'
             try:
                 rcParams[key] = v
             except KeyError as err:
@@ -1430,11 +1430,11 @@ def func(foo, label=None): ...
     arg_names = arg_names[1:]  # remove the first "ax" / self arg
 
     assert {*arg_names}.issuperset(replace_names or []) or varkwargs_name, (
-        "Matplotlib internal error: invalid replace_names ({!r}) for {!r}"
-        .format(replace_names, func.__name__))
+        "Matplotlib internal error: invalid replace_names "
+        f"({replace_names!r}) for {func.__name__!r}")
     assert label_namer is None or label_namer in arg_names, (
-        "Matplotlib internal error: invalid label_namer ({!r}) for {!r}"
-        .format(label_namer, func.__name__))
+        "Matplotlib internal error: invalid label_namer "
+        f"({label_namer!r}) for {func.__name__!r}")
 
     @functools.wraps(func)
     def inner(ax, *args, data=None, **kwargs):

lib/matplotlib/_api/__init__.py

@@ -158,10 +158,10 @@ def check_shape(_shape, **kwargs):
             dim_labels = iter(itertools.chain(
                 'MNLIJKLH',
                 (f"D{i}" for i in itertools.count())))
-            text_shape = ", ".join((str(n)
-                                    if n is not None
-                                    else next(dim_labels)
-                                    for n in target_shape))
+            text_shape = ", ".join(str(n)
+                                   if n is not None
+                                   else next(dim_labels)
+                                   for n in target_shape)
             if len(target_shape) == 1:
                 text_shape += ","
 
@@ -190,8 +190,8 @@ def check_getitem(_mapping, **kwargs):
         return mapping[v]
     except KeyError:
         raise ValueError(
-            "{!r} is not a valid value for {}; supported values are {}"
-            .format(v, k, ', '.join(map(repr, mapping)))) from None
+            f"{v!r} is not a valid value for {k}; supported values are "
+            f"{', '.join(map(repr, mapping))}") from None
 
 
 def caching_module_getattr(cls):
@@ -264,11 +264,11 @@ def method(self, *args, **kwargs):
                 for alias in aliases:
                     method = make_alias(prefix + prop)
                     method.__name__ = prefix + alias
-                    method.__doc__ = "Alias for `{}`.".format(prefix + prop)
+                    method.__doc__ = f"Alias for `{prefix + prop}`."
                     setattr(cls, prefix + alias, method)
         if not exists:
             raise ValueError(
-                "Neither getter nor setter exists for {!r}".format(prop))
+                f"Neither getter nor setter exists for {prop!r}")
 
     def get_aliased_and_aliases(d):
         return {*d, *(alias for aliases in d.values() for alias in aliases)}

lib/matplotlib/_cm.py

@@ -155,7 +155,7 @@ def _g34(x): return 2 * x
 def _g35(x): return 2 * x - 0.5
 def _g36(x): return 2 * x - 1
 
-gfunc = {i: globals()["_g{}".format(i)] for i in range(37)}
+gfunc = {i: globals()[f"_g{i}"] for i in range(37)}
 
 _gnuplot_data = {
         'red': gfunc[7],

lib/matplotlib/_fontconfig_pattern.py

@@ -59,10 +59,10 @@ def _make_fontconfig_parser():
     def comma_separated(elem):
         return elem + ZeroOrMore(Suppress(",") + elem)
 
-    family = Regex(r"([^%s]|(\\[%s]))*" % (_family_punc, _family_punc))
+    family = Regex(fr"([^{_family_punc}]|(\\[{_family_punc}]))*")
     size = Regex(r"([0-9]+\.?[0-9]*|\.[0-9]+)")
     name = Regex(r"[a-z]+")
-    value = Regex(r"([^%s]|(\\[%s]))*" % (_value_punc, _value_punc))
+    value = Regex(fr"([^{_value_punc}]|(\\[{_value_punc}]))*")
     # replace trailing `| name` by oneOf(_CONSTANTS) in mpl 3.9.
     prop = Group((name + Suppress("=") + comma_separated(value)) | name)
     return (

lib/matplotlib/_mathtext.py

@@ -64,8 +64,8 @@ def get_unicode_index(symbol, math=False):  # Publicly exported.
         return tex2uni[symbol.strip("\\")]
     except KeyError as err:
         raise ValueError(
-            "'{}' is not a valid Unicode character or TeX/Type1 symbol"
-            .format(symbol)) from err
+            f"{symbol!r} is not a valid Unicode character or TeX/Type1 symbol"
+            ) from err
 
 
 VectorParse = namedtuple("VectorParse", "width height depth glyphs rects",
@@ -530,7 +530,7 @@ def _get_glyph(self, fontname, font_class, sym):
         except ValueError:
             uniindex = ord('?')
             found_symbol = False
-            _log.warning("No TeX to Unicode mapping for {!a}.".format(sym))
+            _log.warning(f"No TeX to Unicode mapping for {sym!a}.")
 
         fontname, uniindex = self._map_virtual_font(
             fontname, font_class, uniindex)
@@ -576,9 +576,9 @@ def _get_glyph(self, fontname, font_class, sym):
                 if (fontname in ('it', 'regular')
                         and isinstance(self, StixFonts)):
                     return self._get_glyph('rm', font_class, sym)
-                _log.warning("Font {!r} does not have a glyph for {!a} "
-                             "[U+{:x}], substituting with a dummy "
-                             "symbol.".format(new_fontname, sym, uniindex))
+                _log.warning(f"Font {new_fontname!r} does not have a glyph "
+                             f"for {sym!a} [U+{uniindex:x}], substituting "
+                             "with a dummy symbol.")
                 font = self._get_font('rm')
                 uniindex = 0xA4  # currency char, for lack of anything better
                 slanted = False
@@ -752,7 +752,7 @@ def _map_virtual_font(self, fontname, font_class, uniindex):
 
         return fontname, uniindex
 
-    @functools.lru_cache()
+    @functools.lru_cache
     def get_sized_alternatives_for_symbol(self, fontname, sym):
         fixes = {
             '\\{': '{', '\\}': '}', '\\[': '[', '\\]': ']',
@@ -1083,7 +1083,7 @@ def __init__(self, elements):
         self.glue_order   = 0    # The order of infinity (0 - 3) for the glue
 
     def __repr__(self):
-        return '%s<w=%.02f h=%.02f d=%.02f s=%.02f>[%s]' % (
+        return '{}<w={:.02f} h={:.02f} d={:.02f} s={:.02f}>[{}]'.format(
             super().__repr__(),
             self.width, self.height,
             self.depth, self.shift_amount,

lib/matplotlib/_type1font.py

@@ -140,7 +140,7 @@ def _escape(cls, match):
         except KeyError:
             return chr(int(group, 8))
 
-    @functools.lru_cache()
+    @functools.lru_cache
     def value(self):
         if self.raw[0] == '(':
             return self._escapes_re.sub(self._escape, self.raw[1:-1])

lib/matplotlib/animation.py

@@ -536,7 +536,7 @@ def output_args(self):
             args.extend(['-b', '%dk' % self.bitrate])  # %dk: bitrate in kbps.
         args.extend(extra_args)
         for k, v in self.metadata.items():
-            args.extend(['-metadata', '%s=%s' % (k, v)])
+            args.extend(['-metadata', f'{k}={v}'])
 
         return args + ['-y', self.outfile]