matplotlit绘制图像出现空白怎么解决？

Question

python用matplotlib，sklearn绘制图像，绘制出鸢尾花图像，代码运行绘制不出来图像，是一片空白。正确图片如下图。

---

from sklearn import datasets
from sklearn import svm
from sklearn.decomposition import PCA
from matplotlib import pyplot as plt
from matplotlib import patches as pch
from mpl_toolkits.mplot3d import Axes3D
import matplotlib

plt.rcParams['font.sans-serif'] = ['SimHei']  # 设置正常的中文字体
# matplotlib.rcParams['font.family'] = 'SimHei'
matplotlib.rcParams['font.size'] = 10
matplotlib.rcParams['axes.unicode_minus'] = False

v_iris = datasets.load_iris()  # 加载数据赋值给变量
x = v_iris.data[:, 0]  # 取数据集第0列，表示萼片的长度，[:0]就是所有行的第0个数据
y = v_iris.data[:, 1]
z = v_iris.data[:, 2]
zz = v_iris.data[:, 3]
species = v_iris.target
v_reuced = PCA(n_components=3).fit_transform(v_iris.data)
v_fig = plt.figure(figsize=[8, 8])
v_ax = Axes3D(v_fig)
# v_ax.set_title('鸢尾花降维分类',size=18)
v_ax.scatter(v_reuced[:, 0], v_reuced[:, 1], v_reuced[:, 2], c=species)
# v_ax.scatter(z, x, zz, c=species)
v_ax.set_xlabel('x')
v_ax.set_ylabel('y')
v_ax.set_zlabel('z')
# v_ax.xaxis.set_ticklabels(())
# v_ax.yaxis.set_ticklabels(())
# v_ax.zaxis.set_ticklabels(())
plt.savefig("iris_mplot3dpca4")
plt.show()