如何从 pandas DatetimeIndex 中提取并进一步测试日期列表？

Question

There are really two parts to this Question as I am still learning.

date_list = pd.date_range(2019-09-24, 2019-09-26)

will return an object

DatetimeIndex( ['2019-09-24', '2019-09-25'] , dtype='datetime64[ns]', freq='D')

However, I just wanted the List in the format it returns shown above. I tried appending .tolist() but it then returns timestamps in a list eg.

Timestamp('2019-09-24 00:00:00', freq='D')

I then used .date which seems to work

print(date_list[0])

2019-09-24

Is this the best method to use?

Then I came to testing it, I understand this test maybe unnecessary but for the purpose of learning:

def datetimeindex(dates):
    start = dates['from_date']
    end = dates['to_date']
    date_list = pd.date_range(start, end).date
    print(date_list[0])
    return date_list[0]


 def test_datetimeindex(self):
        dates = {"from_date": "2019-09-24",
                "to_date": "2019-09-27"}
        actual = datetimeindex(dates)
        expected = "2019-09-24"
        self.assertEqual(expected, actual)

I get this error:

AssertionError: '2019-09-24'.= datetime,date(2019, 9, 24)

Why is the print different to the return? If I pass this to another method, what will it actually pass, 2019-09-24 or datetime.date(2019, 9, 24)?

I can not assert against datetime.date(2019, 9, 24) as it is not a string, so not sure what to do?

Thanks

EDIT: This returned what I wanted. which reminded me that print() is always to string, so makes sense.

return str(date_list[0])

Answer 1

You can create a list of dates in string format using this method

[i.strftime("%Y-%m-%d") for i in pd.date_range(start=start_date, end=end_date)]