这种写法后续会用到。。。

plt.savefig("test.png")

"""
================================
Recognizing hand-written digits
================================

This example shows how scikit-learn can be used to recognize images of
hand-written digits, from 0-9.
"""

print(__doc__)

# Author: Gael Varoquaux <gael dot varoquaux at normalesup dot org>
# License: BSD 3 clause

# Standard scientific Python imports
import matplotlib.pyplot as plt

# Import datasets, classifiers and performance metrics
from sklearn import datasets, svm, metrics
from sklearn.model_selection import train_test_split

###############################################################################
# Digits dataset
# --------------
#
# The digits dataset consists of 8x8
# pixel images of digits. The ``images`` attribute of the dataset stores
# 8x8 arrays of grayscale values for each image. We will use these arrays to
# visualize the first 4 images. The ``target`` attribute of the dataset stores
# the digit each image represents and this is included in the title of the 4
# plots below.
#
# Note: if we were working from image files (e.g., 'png' files), we would load
# them using :func:`matplotlib.pyplot.imread`.

digits = datasets.load_digits()

_, axes = plt.subplots(nrows=1, ncols=4, figsize=(10, 3))
for ax, image, label in zip(axes, digits.images, digits.target):
    ax.set_axis_off()
    ax.imshow(image, cmap=plt.cm.gray_r, interpolation='nearest')
    ax.set_title('Training: %i' % label)
plt.savefig("test.png")