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)