python - Creating numpy linspace out of datetime

Question

I'm writing a script that plots some data with dates on the x axis (in matplotlib). I need to create a numpy.linspace out of those dates in order to create a spline afterwards. Is it possible to do that?

What I've tried:

import datetime
import numpy as np

dates = [
    datetime.datetime(2015, 7, 2, 0, 31, 41),
    datetime.datetime(2015, 7, 2, 1, 35),
    datetime.datetime(2015, 7, 2, 2, 37, 9),
    datetime.datetime(2015, 7, 2, 3, 59, 16),
    datetime.datetime(2015, 7, 2, 5, 2, 23)
]

x = np.linspace(min(dates), max(dates), 500)

It throws this error:

TypeError: unsupported operand type(s) for *: 'datetime.datetime' and 'float'

I've also tried converting datetime to np.datetime64, but that doesn't work as well:

dates = [np.datetime64(i) for i in dates]
x = np.linspace(min(dates), max(dates), 500)

Error:

TypeError: ufunc multiply cannot use operands with types dtype('<M8[us]') and dtype('float64')

Answer 1

Have you considered using pandas? Using an approach from this possible duplicate question, you can make use of np.linspace in the following way

import pandas as pd

start = pd.Timestamp('2015-07-01')
end = pd.Timestamp('2015-08-01')
t = np.linspace(start.value, end.value, 100)
t = pd.to_datetime(t)

To obtain an np.array of the linear timeseries

In [3]: np.asarray(t)
Out[3]: 
array(['2015-06-30T17:00:00.000000000-0700',
       '2015-07-01T00:30:54.545454592-0700',
       '2015-07-01T08:01:49.090909184-0700',
               ...
       '2015-07-31T01:58:10.909090816-0700',
       '2015-07-31T09:29:05.454545408-0700',
       '2015-07-31T17:00:00.000000000-0700'], dtype='datetime64[ns]')