Figuring out the time format from datetime number

Question

I have a dataset whose exact format or origin is unknown to me. I know that the time that the data was recorded is around September 2017, and the time column contains the following numbers:

[736887.61095486],
[736887.61096065],
...,
[736905.61505787],
[736905.61506366],

Any ideas how can I convert this to proper DateTime and use this column as my DataFrame index?

Answer 1

Now that we know that your numbers represent the number of days from January 0, 0000, we can use module datetime to reconstruct their calendar values:

import pandas as pd
from datetime import datetime, timedelta
data = ... # Your data
pd.Series(timedelta(d[0]) for d in data) + datetime(1,1,1)
#0   2018-07-13 14:39:46.499903
#1   2018-07-13 14:39:47.000162
#2   2018-07-31 14:45:40.999972
#3   2018-07-31 14:45:41.500221

Apparently, the date January 0, 0000 in Python corresponds to the year #1, month #1, and day #1.