1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
|
"""
======================
Compose custom legends
======================
Composing custom legends piece-by-piece.
.. note::
For more information on creating and customizing legends, see the following
pages:
* :ref:`legend_guide`
* :doc:`/gallery/text_labels_and_annotations/legend_demo`
Sometimes you don't want a legend that is explicitly tied to data that
you have plotted. For example, say you have plotted 10 lines, but don't
want a legend item to show up for each one. If you simply plot the lines
and call ``ax.legend()``, you will get the following:
"""
import matplotlib.pyplot as plt
import numpy as np
# sphinx_gallery_thumbnail_number = 2
import matplotlib as mpl
from matplotlib import cycler
# Fixing random state for reproducibility
np.random.seed(19680801)
# %%
N = 10
data = (np.geomspace(1, 10, 100) + np.random.randn(N, 100)).T
cmap = plt.cm.coolwarm
mpl.rcParams['axes.prop_cycle'] = cycler(color=cmap(np.linspace(0, 1, N)))
fig, ax = plt.subplots()
lines = ax.plot(data)
# %%
# Since the data does not have any labels, creating a legend requires
# us to define the icons and labels.
# In this case, we can compose a legend using Matplotlib objects that aren't
# explicitly tied to the data that was plotted. For example:
from matplotlib.lines import Line2D
custom_lines = [Line2D([0], [0], color=cmap(0.), lw=4),
Line2D([0], [0], color=cmap(.5), lw=4),
Line2D([0], [0], color=cmap(1.), lw=4)]
fig, ax = plt.subplots()
lines = ax.plot(data)
ax.legend(custom_lines, ['Cold', 'Medium', 'Hot'])
# %%
# There are many other Matplotlib objects that can be used in this way. In the
# code below we've listed a few common ones.
from matplotlib.lines import Line2D
from matplotlib.patches import Patch
legend_elements = [Line2D([0], [0], color='b', lw=4, label='Line'),
Line2D([0], [0], marker='o', color='w', label='Scatter',
markerfacecolor='g', markersize=15),
Patch(facecolor='orange', edgecolor='r',
label='Color Patch')]
# Create the figure
fig, ax = plt.subplots()
ax.legend(handles=legend_elements, loc='center')
plt.show()
|
