如何将`numpy.datetime64`列表转换为`matplotlib.dates`？

问题描述：

这里是我的简单对象：如何将`numpy.datetime64`列表转换为`matplotlib.dates`？

[numpy.datetime64('2017-01-03T00:00:00.000000000'), 
numpy.datetime64('2017-01-04T00:00:00.000000000'), 
numpy.datetime64('2017-01-05T00:00:00.000000000'), 
numpy.datetime64('2017-01-06T00:00:00.000000000'), 
numpy.datetime64('2017-01-09T00:00:00.000000000'), 
numpy.datetime64('2017-01-10T00:00:00.000000000'), 
numpy.datetime64('2017-01-11T00:00:00.000000000'), 
numpy.datetime64('2017-01-12T00:00:00.000000000'), 
numpy.datetime64('2017-01-13T00:00:00.000000000'), 
numpy.datetime64('2017-01-16T00:00:00.000000000'), 
numpy.datetime64('2017-01-17T00:00:00.000000000'), 
numpy.datetime64('2017-01-18T00:00:00.000000000'), 
numpy.datetime64('2017-01-19T00:00:00.000000000'), 
numpy.datetime64('2017-01-20T00:00:00.000000000'), 
numpy.datetime64('2017-01-23T00:00:00.000000000'), 
numpy.datetime64('2017-01-24T00:00:00.000000000'), 
numpy.datetime64('2017-01-25T00:00:00.000000000'), 
numpy.datetime64('2017-01-26T00:00:00.000000000'), 
numpy.datetime64('2017-01-27T00:00:00.000000000'), 
numpy.datetime64('2017-02-01T00:00:00.000000000')]

而是采用了环空列表转换一个接一个，有没有任何捷径？谢谢。

嗯，列表内涵/发电机表达式？但他们仍然一个接一个地处理项目。 – user3159253

https://stackoverflow.com/questions/34843513/python-matplotlib-dates-date2num-converting-numpy-array-to-matplotlib-datetimes这有帮助吗？ –

映射函数？ – wwii

答

我最喜欢的解决方案是这个线程似乎有点隐藏： Converting between datetime, Timestamp and datetime64，这是使用tolist()。由于tolist()返回不同类型，根据阵列类型，需要转换为ms才能获得datetime对象。可以直接用matplotlib绘制对象，也可以在其上应用matplotlib.dates.date2num()。

所以如果a是numpy的阵列如上，

x = a.astype("M8[ms]").tolist()

导致日期时间的对象的列表。

完整的示例：

import numpy as np 
import matplotlib.pyplot as plt 
from datetime import datetime 
import matplotlib.dates as mdates 

a = np.array([np.datetime64('2017-01-03T00:00:00.000000000'), 
    np.datetime64('2017-01-04T00:00:00.000000000'), 
    np.datetime64('2017-01-05T00:00:00.000000000'), 
    np.datetime64('2017-01-06T00:00:00.000000000'), 
    np.datetime64('2017-01-09T00:00:00.000000000'), 
    np.datetime64('2017-01-10T00:00:00.000000000'), 
    np.datetime64('2017-01-11T00:00:00.000000000'), 
    np.datetime64('2017-01-12T00:00:00.000000000'), 
    np.datetime64('2017-01-13T00:00:00.000000000'), 
    np.datetime64('2017-01-16T00:00:00.000000000'), 
    np.datetime64('2017-01-17T00:00:00.000000000'), 
    np.datetime64('2017-01-18T00:00:00.000000000'), 
    np.datetime64('2017-01-19T00:00:00.000000000'), 
    np.datetime64('2017-01-20T00:00:00.000000000'), 
    np.datetime64('2017-01-23T00:00:00.000000000'), 
    np.datetime64('2017-01-24T00:00:00.000000000'), 
    np.datetime64('2017-01-25T00:00:00.000000000'), 
    np.datetime64('2017-01-26T00:00:00.000000000'), 
    np.datetime64('2017-01-27T00:00:00.000000000'), 
    np.datetime64('2017-02-01T00:00:00.000000000')]) 

x = a.astype("M8[ms]").tolist() 
y = np.random.rand(len(a)) 

plt.plot(x, y, color="limegreen") 

plt.show()

如何将`numpy.datetime64`列表转换为`matplotlib.dates`？

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