Question

I currently have my Django custom template filter like this:

from django import template

register = template.Library()

@register.filter
def duration(value):
    hours   = value / 60
    minutes = value % 60

    hours_string   = str(hours)   + (" hours"   if hours   > 1 else " hour"  ) if hours   else ""
    minutes_string = str(minutes) + (" minutes" if minutes > 1 else " minute") if minutes else ""

    return ' '.join("{hours} {minutes}".format(hours=hours_string, minutes=minutes_string).split())

Some possible outputs:

1 hour 25 minutes
2 hours
45 minutes
3 hours 1 minute

The ' '.join(....split()) trick was something I got from this solution. I realize I only need to check for the extra string at either the beginning or the end of the string (for when it’s 0 hours or 0 minutes), but it seems to do the trick and maybe it’s easier to read than regular expression to some people.

I also feel that I am violating DRY since I am repeating almost the exact same if-then block twice. I was thinking of something like…

for i, unit in enumerate([hours, minutes]):
    # Do some code.

return ' '.join("{hours} {minutes}".format(hours=value[0], minutes=value[1]).split())

but I couldn’t figure out how to choose between “hour(s)” or “minute(s)” without another if-then block. Also the two short-hand if-then per line also looks a bit ugly too…

I’ll appreciate any suggestions or tips. Thanks!

Answer 1

import datetime
def pprint(val):
   if val == 1:
      return '1 minute'
   x = str(datetime.timedelta(minutes=val))[:-3].split(':')
   r = ''
   if int(x[0]):
       r += x[0]+' hours' if int(x[0]) > 1 else x[0]+' hour'
   if int(x[1]):
       r += ' %s minutes' % int(x[1]) if int(x[1]) > 1 else ' %s minute' % int(x[0])
   return r.strip()

Sample run:

>>> pprint(65)
'1 hour 5 minutes'
>>> pprint(1)
'1 minute'
>>> pprint(60)
'1 hour'
>>> pprint(61)
'1 hour 1 minute'

You can easily expand this to include days as well, but since you specifically mentioned only hours and minutes I adjusted the method.

The main heavy lifting is done by datetime.timedelta, the rest is just string parsing.