Identify if datetime is in timespec='milliseconds'-CodePudding

I have following datetimes:

a = "2018-07-13T00:00:00 00:00"
b = "2018-07-13T00:00:00.000000 00:00"

I want to check if a datetime has timespec='milliseconds'. So my function should return False for a and True for b Any ideas how to solve this?

CodePudding user response：

Assuming you have strings as in the question.

If you only have the two formats above, you could only check the length:

def has_ms(s):
    return len(s) == 32

You could also perform a complete match of the format in b:

def is_ms_strict_format(s):
    import re
    return bool(re.match(r'\d{4}-\d{2}-\d{2}T(\d{2}:){2}\d{2}\.\d{6}\ \d{2}:\d{2}', s))

examples:

>>> has_ms(a)
False
>>> has_ms(b)
True
>>> is_ms_strict_format(a)
False
>>> is_ms_strict_format(b)
True

CodePudding user response：

Assuming you are dealing with datetime string in iso format

from datetime import datetime

def has_microseconds(dt):
    return not datetime.fromisoformat(dt).isoformat(timespec='seconds') == dt

a = "2018-07-13T00:00:00 00:00" # seconds
b = "2018-07-13T00:00:00.000000 00:00" # microseconds
c = "2018-07-13T00:00:00.000 00:00" # milliseconds

print(has_microseconds(a))
print(has_microseconds(b))
print(has_microseconds(c))

output

False
True
True

Note this will not work (needs refinement) if the string is in iso format, but has only hours [and minutes] but not seconds.

UPDATE: Here is function that will return exact timespec given iso-format string

from datetime import datetime

def get_timespec(dt):
    specs = ['hours', 'minutes', 'seconds', 'milliseconds', 'microseconds']
    for timespec in specs:
        if datetime.fromisoformat(dt).isoformat(timespec=timespec) == dt:
            return timespec

sample = ["2018-07-13T00 00:00", # hours
          "2018-07-13T00:00 00:00", # minutes
          "2018-07-13T00:00:00 00:00", # seconds
          "2018-07-13T00:00:00.000 00:00", # milliseconds
          "2018-07-13T00:00:00.000000 00:00"] # microseconds

for dt in sample:
    print(get_timespec(dt))

output

hours
minutes
seconds
milliseconds
microseconds