Confusion Matrix
Utility function for visualizing confusion matrices via matplotlib
from mlxtend.plotting import plot_confusion_matrix
Overview
Confusion Matrix
For more information on confusion matrices, please see mlxtend.evaluate.confusion_matrix
.
References
- -
Example 1 - Binary
from mlxtend.plotting import plot_confusion_matrix
import matplotlib.pyplot as plt
import numpy as np
binary = np.array([[4, 1],
[1, 2]])
fig, ax = plot_confusion_matrix(conf_mat=binary)
plt.show()
Example 2 - Binary absolute and relative with colorbar
binary = np.array([[4, 1],
[1, 2]])
fig, ax = plot_confusion_matrix(conf_mat=binary,
show_absolute=True,
show_normed=True,
colorbar=True)
plt.show()
Example 3 - Multiclass relative
multiclass = np.array([[2, 1, 0, 0],
[1, 2, 0, 0],
[0, 0, 1, 0],
[0, 0, 0, 1]])
fig, ax = plot_confusion_matrix(conf_mat=multiclass,
colorbar=True,
show_absolute=False,
show_normed=True)
plt.show()
API
plot_confusion_matrix(conf_mat, hide_spines=False, hide_ticks=False, figsize=None, cmap=None, colorbar=False, show_absolute=True, show_normed=False)
Plot a confusion matrix via matplotlib. Parameters
-
conf_mat
: array-like, shape = [n_classes, n_classes]Confusion matrix from evaluate.confusion matrix.
-
hide_spines
: bool (default: False)Hides axis spines if True.
-
hide_ticks
: bool (default: False)Hides axis ticks if True
-
figsize
: tuple (default: (2.5, 2.5))Height and width of the figure
-
cmap
: matplotlib colormap (default:None
)Uses matplotlib.pyplot.cm.Blues if
None
-
colorbar
: bool (default: False)Shows a colorbar if True
-
show_absolute
: bool (default: True)Shows absolute confusion matrix coefficients if True. At least one of
show_absolute
orshow_normed
must be True. -
show_normed
: bool (default: False)Shows normed confusion matrix coefficients if True. The normed confusion matrix coefficients give the proportion of training examples per class that are assigned the correct label. At least one of
show_absolute
orshow_normed
must be True. Returns -
fig, ax
: matplotlib.pyplot subplot objectsFigure and axis elements of the subplot. Examples
For usage examples, please see http://rasbt.github.io/mlxtend/user_guide/plotting/plot_confusion_matrix/