Merge pull request matplotlib#19204 from rcomer/date-tick-example

DOC: Clarify Date Format Example

Author: tacaswell

examples/text_labels_and_annotations/date.py

@@ -39,29 +39,30 @@
 fig, ax = plt.subplots()
 ax.plot('date', 'adj_close', data=data)
 
-# Major ticks every 6 months
+# Major ticks every 6 months.
 fmt_half_year = mdates.MonthLocator(interval=6)
 ax.xaxis.set_major_locator(fmt_half_year)
 
-# Minor ticks every month
+# Minor ticks every month.
 fmt_month = mdates.MonthLocator()
 ax.xaxis.set_minor_locator(fmt_month)
 
-# Text in the x axis will be displayed in 'YYYY-mm' format
+# Text in the x axis will be displayed in 'YYYY-mm' format.
 ax.xaxis.set_major_formatter(mdates.DateFormatter('%Y-%m'))
 
 # Round to nearest years.
 datemin = np.datetime64(data['date'][0], 'Y')
 datemax = np.datetime64(data['date'][-1], 'Y') + np.timedelta64(1, 'Y')
 ax.set_xlim(datemin, datemax)
 
-# Format the coords message box
+# Format the coords message box, i.e. the numbers displayed as the cursor moves
+# across the axes within the interactive GUI.
 ax.format_xdata = mdates.DateFormatter('%Y-%m')
-ax.format_ydata = lambda x: '$%1.2f' % x  # format the price.
+ax.format_ydata = lambda x: f'${x:.2f}'  # Format the price.
 ax.grid(True)
 
-# rotates and right aligns the x labels, and moves the bottom of the
-# axes up to make room for them
+# Rotates and right aligns the x labels, and moves the bottom of the
+# axes up to make room for them.
 fig.autofmt_xdate()
 
 plt.show()