为什么这个图在添加散点时失败，但在删除散点时却有效？

我正在使用以下内容来绘制 x 日期和 y 小数。如果没有注释行（散点），它的效果很好，但是如果您取消注释它，它会在一个 x 轴上显示所有内容

我缺少什么？

thanks

import matplotlib.pyplot as plt
import datetime

fig = plt.figure(facecolor="#979899")
ax = plt.gca()
ax.set_facecolor("#d1d1d1")
plt.grid(True)
plt.title("This is a title",fontsize=16)

plt.xticks([datetime.date(2018,11,20),datetime.date(2018,11,21),datetime.date(2018,11,22)],["11/20","11/21","11/22"])
plt.yticks([0.0,0.1,0.2,0.3,0.4,0.5,0.6,0.7,0.8,0.9,1.0],["0.0","0.1","0.2","0.3","0.4","0.5","0.6","0.7","0.8","0.9","1.0"])

x1 = [datetime.date(2018,11,20),datetime.date(2018,11,21),datetime.date(2018,11,22)]
y1 = [0.18,0.32,0.21]

for i,item in enumerate(y1):
    xP = x1[i]
    yP = y1[i]
    plt.text(xP,yP,str(item)+"%",fontsize=11)

#plt.scatter(x1,y1)
plt.plot(x1,y1)
plt.show()

问题是集合的自动缩放。This is https://github.com/matplotlib/matplotlib/issues/7413根本问题早已为人所知，但很难解决。在某些情况下，当值彼此太接近时，自动缩放无法可靠地工作。不幸的是，约会时经常出现这种情况。

import matplotlib.pyplot as plt
import datetime

fig, ax = plt.subplots()

x1 = [datetime.date(2018,11,20),datetime.date(2018,11,22)]
y1 = [1,2]

plt.scatter(x1,y1, s=50, color="red")
plt.plot(x1,y1, marker="o", ms=3, zorder=3)

plt.show()

但是，您可以创建一个plot第一的。这将充分确定自动缩放限制。之后绘制scatter.

import matplotlib.pyplot as plt
import datetime

fig, ax = plt.subplots()

x1 = [datetime.date(2018,11,20),datetime.date(2018,11,22)]
y1 = [1,2]

plt.plot(x1,y1, marker="o", ms=3)
plt.scatter(x1,y1, s=50, color="red")

plt.show()