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"""
===========
Stairs Demo
===========
This example demonstrates the use of `~.matplotlib.pyplot.stairs` for stepwise
constant functions. A common use case is histogram and histogram-like data
visualization.
"""
import matplotlib.pyplot as plt
import numpy as np
from matplotlib.patches import StepPatch
np.random.seed(0)
h, edges = np.histogram(np.random.normal(5, 3, 5000),
bins=np.linspace(0, 10, 20))
fig, axs = plt.subplots(3, 1, figsize=(7, 15))
axs[0].stairs(h, edges, label='Simple histogram')
axs[0].stairs(h, edges + 5, baseline=50, label='Modified baseline')
axs[0].stairs(h, edges + 10, baseline=None, label='No edges')
axs[0].set_title("Step Histograms")
axs[1].stairs(np.arange(1, 6, 1), fill=True,
label='Filled histogram\nw/ automatic edges')
axs[1].stairs(np.arange(1, 6, 1)*0.3, np.arange(2, 8, 1),
orientation='horizontal', hatch='//',
label='Hatched histogram\nw/ horizontal orientation')
axs[1].set_title("Filled histogram")
patch = StepPatch(values=[1, 2, 3, 2, 1],
edges=range(1, 7),
label=('Patch derived underlying object\n'
'with default edge/facecolor behaviour'))
axs[2].add_patch(patch)
axs[2].set_xlim(0, 7)
axs[2].set_ylim(-1, 5)
axs[2].set_title("StepPatch artist")
for ax in axs:
ax.legend()
plt.show()
# %%
# *baseline* can take an array to allow for stacked histogram plots
A = [[0, 0, 0],
[1, 2, 3],
[2, 4, 6],
[3, 6, 9]]
for i in range(len(A) - 1):
plt.stairs(A[i+1], baseline=A[i], fill=True)
# %%
# Comparison of `.pyplot.step` and `.pyplot.stairs`
# -------------------------------------------------
#
# `.pyplot.step` defines the positions of the steps as single values. The steps
# extend left/right/both ways from these reference values depending on the
# parameter *where*. The number of *x* and *y* values is the same.
#
# In contrast, `.pyplot.stairs` defines the positions of the steps via their
# bounds *edges*, which is one element longer than the step values.
bins = np.arange(14)
centers = bins[:-1] + np.diff(bins) / 2
y = np.sin(centers / 2)
plt.step(bins[:-1], y, where='post', label='step(where="post")')
plt.plot(bins[:-1], y, 'o--', color='grey', alpha=0.3)
plt.stairs(y - 1, bins, baseline=None, label='stairs()')
plt.plot(centers, y - 1, 'o--', color='grey', alpha=0.3)
plt.plot(np.repeat(bins, 2), np.hstack([y[0], np.repeat(y, 2), y[-1]]) - 1,
'o', color='red', alpha=0.2)
plt.legend()
plt.title('step() vs. stairs()')
plt.show()
# %%
#
# .. admonition:: References
#
# The use of the following functions, methods, classes and modules is shown
# in this example:
#
# - `matplotlib.axes.Axes.stairs` / `matplotlib.pyplot.stairs`
# - `matplotlib.patches.StepPatch`
#
# .. tags::
#
# plot-type: stairs
# level: intermediate
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