Update example Step Demo

timhoffm · timhoffm · commit f82fa8ad7c5f · 2019-01-10T17:47:23.000+01:00
diff --git a/examples/lines_bars_and_markers/step_demo.py b/examples/lines_bars_and_markers/step_demo.py
@@ -3,30 +3,29 @@
 Step Demo
 =========
 
-Example step plots.
+This example demonstrates the use of `.pyplot.step` for piece-wise constant
+curves. In particular, it illustrates the effect of the parameter *where*
+on the step position.
+
+The circular markers created with `.pyplot.plot` show the actual data
+positions so that it's easier to see the effect of *where*.
+
 """
 import numpy as np
 from numpy import ma
 import matplotlib.pyplot as plt
 
-x = np.arange(1, 7, 0.4)
-y0 = np.sin(x)
-y = y0.copy() + 2.5
+x = np.arange(0, 14)
+y = np.sin(x / 2)
 
-plt.step(x, y, label='pre (default)')
+plt.step(x, y + 2, label='pre (default)')
+plt.plot(x, y + 2, 'C0o', alpha=0.5)
 
-y -= 0.5
-plt.step(x, y, where='mid', label='mid')
+plt.step(x, y + 1, where='mid', label='mid')
+plt.plot(x, y + 1, 'C1o', alpha=0.5)
 
-y -= 0.5
 plt.step(x, y, where='post', label='post')
+plt.plot(x, y, 'C2o', alpha=0.5)
 
-y = ma.masked_where((y0 > -0.15) & (y0 < 0.15), y - 0.5)
-plt.step(x, y, label='masked (pre)')
-
-plt.legend()
-
-plt.xlim(0, 7)
-plt.ylim(-0.5, 4)
-
-plt.show()
+plt.legend(title='Parameter where:')
+plt.show()
