matplotlib三维散点图日期

Question

我有一份日期列表，格式为15/10/2017

我尝试了以下内容

from matplotlib import pyplot
import pandas as pd

dates = ['15/10/2016', '16/10/2016', "17/10/2015", "15/10/2014"]
dates_formatted = [pd.to_datetime(d) for d in dates ]
x = [1,2,3,4]
z = [5,6,7,8]

pyplot.scatter(x, dates_formatted, z)
pyplot.show()

它会抛出错误TypeError: ufunc 'sqrt' not supported for the input types, and the inputs could not be safely coerced to any supported types according to the casting rule ''safe''

它显示它是否是2D。 例如pyplot.scatter(x, dates_formatted)

我也试过以下

ax = Axes3D(fig)
ax = fig.add_subplot(111,projection='3d')
ax.scatter(x, dates_formatted, y)
pyplot.show()

它抛出错误Float() argument must be a string or number

Answer 1

告诉matplotlib如何将字符串转换为坐标系并不总是微不足道的。 为什么不简单地为轴设置自定义刻度标签？

import pandas as pd
from mpl_toolkits.mplot3d import Axes3D
import matplotlib.pyplot as plt

fig = plt.figure('scatter dates')
ax = fig.add_subplot(111, projection='3d')
dates = ['15/10/2016', '16/10/2016', "17/10/2015", "15/10/2014"]
dates_formatted = [pd.to_datetime(d) for d in dates ]
x = [1,2,3,4]
y = [9,10,11,12]
z = [5,6,7,8]

ax.scatter(x, y, z)
ax.xaxis.set_ticks(x)
ax.xaxis.set_ticklabels(dates_formatted)
plt.show()

Answer 2

Scatter期待一个数字。 因此，您可以将日期转换为数字，如下所示：

y = [ (d-min(dates_formatted)).days for d in dates_formatted]

现在您可以将数据绘制为

pyplot.scatter(x, y)

对于3D情节，你可以试试这样的......

import pandas as pd
import matplotlib.pyplot as plt
from mpl_toolkits.mplot3d import Axes3D

plt.ion()
x = [1,2,3,4]
z = [5,6,7,8]
dates = ['15/10/2016', '16/10/2016', "17/10/2015", "15/10/2014"]
dates_formatted = [pd.to_datetime(d) for d in dates]

y = [ (d-min(dates_formatted)).days for d in dates_formatted]

fig = plt.figure()
ax = fig.add_subplot(111, projection='3d')
plt.scatter(x, y, z)

现在的y轴是天。 您可以通过查找日期字符串并将其更改回来进行更改...

dt = [ pd.Timedelta(d) + min(dates_formatted)  for d in  ax.get_yticks()]

将这些转换为字符串......

dtStr = [d.isoformat() for d in dt]

并把它们放回去

ax.set_yticklabels(dtStr)