plt.annotate(C[j, i], xy=(i, j), horizontalalignment='center', verticalalignment='center')
时间: 2023-06-26 16:09:59 浏览: 43
这段代码主要是在图表中添加注释。其中,C[j, i]是注释的文本内容,xy=(i, j)是注释的位置,horizontalalignment和verticalalignment则分别表示文本水平和垂直方向的对齐方式。具体可以参考matplotlib的官方文档:https://matplotlib.org/stable/api/_as_gen/matplotlib.pyplot.annotate.html
相关问题
from sklearn.metrics import confusion_matrix import matplotlib.pyplot as plt plt.rc('figure',figsize=(5,5)) cm = confusion_matrix(y,yp) plt.matshow(cm,cmap = plt.cm.Blues) # 背景颜色 plt.colorbar() # 颜色标签 # 内部添加图例标签 for x in range(len(cm)): for y in range(len(cm)): plt.annotate(cm[x,y], xy = (x,y), horizontalalignment = 'center', verticalalignment = 'center') plt.ylabel('True Label') plt.xlabel('Predicted Label') plt.title('Cart_train') plt.show() 这段代码哪里有问题
这段代码缺少了一个关键字 `as` 。正确的代码应该是:
```
from sklearn.metrics import confusion_matrix
import matplotlib.pyplot as plt
plt.rc('figure',figsize=(5,5))
cm = confusion_matrix(y,yp)
plt.matshow(cm,cmap = plt.cm.Blues) # 背景颜色
plt.colorbar() # 颜色标签
# 内部添加图例标签
for x in range(len(cm)):
for y in range(len(cm)):
plt.annotate(cm[x,y], xy = (x,y), horizontalalignment = 'center', verticalalignment = 'center')
plt.ylabel('True Label')
plt.xlabel('Predicted Label')
plt.title('Cart_train')
plt.show()
```
此外,变量 `y` 和 `yp` 没有定义,你需要把它们定义在代码之前。
import numpy as np import matplotlib.pyplot as plt # 极坐标螺旋线 r = np.arange(0,3,0.002) theta = 2 * np.pi * r fig = plt.figure(figsize=(8, 8)) ax = fig.add_subplot(111, projection='polar') ax.plot(theta, r) ax.set_rticks([0.5, 1, 1.5, 2, 2.5, 3, 4]) fig, ax = plt.subplots(subplot_kw={'projection': 'polar'}) ax.plot(theta, r, label='Archimedean spiral') ax.plot(theta_intersect, r_intersect, 'ro', label='Intersection point') ax.annotate('Intersection point', xy=(theta_intersect, r_intersect), xytext=(theta_intersect+0.5, r_intersect+0.5), arrowprops=dict(facecolor='black', shrink=0.01), fontsize=10, horizontalalignment='right', verticalalignment='bottom') # 添加注释 ax.annotate('Start Here', xy=(0, 0), xytext=(0.1, 1.2), arrowprops=dict(facecolor='black', shrink=0.05)) ax.annotate('End Here', xy=(10*np.pi, 10*np.pi), xytext=(9.5, 9.5), arrowprops=dict(facecolor='black', shrink=0.05)) ax.legend() plt.show()代码优化
可以考虑将两个子图合并成一个,同时移除不必要的代码注释。代码优化后如下:
```python
import numpy as np
import matplotlib.pyplot as plt
r = np.arange(0, 3, 0.002)
theta = 2 * np.pi * r
fig = plt.figure(figsize=(8, 8))
ax = fig.add_subplot(111, projection='polar')
# 绘制极坐标螺旋线
ax.plot(theta, r, label='Archimedean spiral')
# 设置极坐标刻度
ax.set_rticks([0.5, 1, 1.5, 2, 2.5, 3, 4])
# 添加交点的标记
theta_intersect = np.pi / 4
r_intersect = theta_intersect / (2 * np.pi)
ax.plot(theta_intersect, r_intersect, 'ro', label='Intersection point')
ax.annotate('Intersection point', xy=(theta_intersect, r_intersect), xytext=(theta_intersect+0.5, r_intersect+0.5),
arrowprops=dict(facecolor='black', shrink=0.01), fontsize=10, horizontalalignment='right', verticalalignment='bottom')
# 添加起点和终点的标记
ax.annotate('Start Here', xy=(0, 0), xytext=(0.1, 1.2), arrowprops=dict(facecolor='black', shrink=0.05))
ax.annotate('End Here', xy=(10*np.pi, 10*np.pi), xytext=(9.5, 9.5), arrowprops=dict(facecolor='black', shrink=0.05))
# 添加图例
ax.legend()
plt.show()
```