Why cannot I determine in code that an object is of a DataTime type?

Question

I have a variable v and when I do

print type(v)

I do get

<type 'DateTime'>

but when I do

if type(v) in (datetime, datetime.date, datetime.datetime, datetime.time):

it is NOT true

The question is: Why ?

EDIT:

The type DateTime is a Spotfire specific type.

https://docs.tibco.com/pub/doc_remote/spotfire/7.9.0/TIB_sfire-analyst_7.9.0_api/html/F_Spotfire_Dxp_Data_DataType_DateTime.htm

How was `v` created? You are showing it's printing type 'DateTime'; if I create a datetime object (eg. datetime.datetime.utcnow()) it shows as `` and your if condition is True. — , May 22 '18 at 07:31

Benyamin Jafari · Answer 1 · 2018-07-03T20:05:16.863

2

I tested it and this condition was True.

import datetime


v = datetime.datetime.now()  # maybe your problem is here.
print(type(v))

if type(v) in (datetime, datetime.date, datetime.datetime, datetime.time):
    print("I'm True")

else:
    print("I'm False")

Out:

<type 'datetime.datetime'>
"I'm True"

edited Jul 03 '18 at 20:05

answered May 22 '18 at 07:30

Benyamin Jafari

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score 0 · Accepted Answer · answered May 22 '18 at 11:19

What you would want to use in this case is isinstance

if isinstance(v, (datetime, datetime.date, datetime.datetime, datetime.time)):

On short, the reason is that type(v) is more restrictive and can't use subclasses, as that DataTime I imagine it is.

For a detailed overview of type vs isinstance head over to this question.

Also, note that your type is <type 'DateTime'> and not datetime.datetime. You need to import that DateTime class and used it. Eg:

from x.y.z import DateTime

if type(v) in (..., DateTime, ...):
    ....

If nothing works, you can use `type(v).__name__` which will give you the string `'DateTime'`, maybe this can help you. — foobarna, May 24 '18 at 21:05

Why cannot I determine in code that an object is of a DataTime type?

2 Answers2