time - Rounding up to nearest 30 minutes in python

Question

I have the following code below.

I would like to roundup TIME to the nearest 30 minutes in the hour. For example: 12:00PM or 12:30PM and so on.

EASTERN_NOW = timezone.localtime(timezone.now() + timedelta(minutes=30))

TIME = datetime.time(EASTERN_NOW.time().hour, EASTERN_NOW.time().minute).strftime(
    VALID_TIME_FORMATS[2])

Thanks in advance

Answer 1

To round up to the nearest 30 minutes:

#!/usr/bin/env python3
from datetime import datetime, timedelta

def ceil_dt(dt, delta):
    return dt + (datetime.min - dt) % delta

now = datetime.now()
print(now)    
print(ceil_dt(now, timedelta(minutes=30)))

The formula is suggested by @Mark Dickinson (for a different question).

Output

2015-09-22 19:08:34.839915
2015-09-22 19:30:00

Note: if the input is timezone-aware datetime object such as EASTERN_NOW in your case then you should call timezone.make_aware(rounded_dt.replace(tzinfo=None)) if you want to preserve the rounded local time and to attach the correct tzinfo, otherwise you may get wrong timezone info if the rounding crosses DST boundaries. Or to avoid failing for ambiguous local time, call .localize() manually:

localize = getattr(rounded_dt.tzinfo, 'localize', None)
if localize:
   rounded_dt = localize(rounded_dt.replace(tzinfo=None),
                         is_dst=bool(rounded_dt.dst()))