Format time string in Python 3.3

Question

I am trying to get current local time as a string in the format: year-month-day hour:mins:seconds. Which I will use for logging. By my reading of the documentation I can do this by:

import time
'{0:%Y-%m-%d %H:%M:%S}'.format(time.localtime())

However I get the error:

Traceback (most recent call last):
File "", line 1, in 
ValueError: Invalid format specifier

What am I doing wrong? Is there a better way?

Solution 1

time.localtime returns time.struct_time which does not support strftime-like formatting.

Pass datetime.datetime object which support strftime formatting. (See datetime.datetime.__format__)

>>> import datetime
>>> '{0:%Y-%m-%d %H:%M:%S}'.format(datetime.datetime.now())
'2014-02-07 11:52:21'

Solution 2

And for newer versions of Python (3.6+, https://www.python.org/dev/peps/pep-0498/ purely for completeness), you can use the newer string formatting, ie.

import datetime

today = datetime.date.today()

f'{today:%Y-%m-%d}'
> '2018-11-01'

Solution 3

You can alternatively use time.strftime:

time.strftime('{%Y-%m-%d %H:%M:%S}')

Comments

[markmnl]

is there any downside to using datetime.datetime instead of time?

[markmnl]

OK, I see there differences here: stackoverflow.com/questions/7479777/…, datetime is more suited to my needs, thanks!

[Mad Physicist]

I'm pretty sure the 0: is superfluous for strftime. +1

[Kieveli]

Try this too: f"{datetime.datetime.now():%Y-%m-%d %H:%M:%S}"

[falsetru]

@Kieveli, The question is tagged python-3.3. f-string syntax is available in Python 3.6+. Another answer already mentioned f-string. :)