converting strptime into 'X hours ago'

Question

I have a a date in strptime that I want to show as 'X hours ago'. I can happily convert hours into days and weeks etc. but I don't know how to do the initial sum. Here is how I'm converting the string into strptime:

time.strptime(obj.created_at, '%a %b %d %H:%M:%S +0000 %Y')

p.s. bonus points for figuring out why it won't take %z for '+0000' - am I completely wrong about what this is?

Answer 1

It seems the timesince in Django could help you out without you having to convert. The source for timesince is available here.

Answer 2

Can you use datetime instead? (Or convert whatever you have into datetime?)

>>> import datetime
>>> created_at = datetime.datetime(2009,10,15, 13)
>>> now = datetime.datetime.now()
>>> delta = now - created_at
>>> hours_ago = '%d Hours Ago' % (delta.seconds/60/60)
>>> hours_ago
'5 Hours Ago'

Answer 3

The datetime module is definitely easier to use, but, if you insist, you can do it with the time module instead. I.e.:

>>> import time
>>> fmt = '%a %b %d %H:%M:%S +0000 %Y'
>>> time.strftime(fmt)
'Thu Oct 15 07:54:07 +0000 2009'
>>> createdat = 'Thu Oct 15 02:30:30 +0000 2009'
>>> createdtim = time.strptime(createdat, fmt)
>>> hoursago = (time.time() - time.mktime(createdtim)) / 3600
>>> print hoursago
5.42057559947

One reason the time module is so pesky to use is that it uses two different ways to represent time -- one is a 9-tuple (and that's what you get from strptime), and one is a float "seconds since the epoch" (and that's what you need to do differences); the mktime function translates the former to the latter. Difference in hours is clearly 1/3600 of the difference in seconds -- you'll have to decide how to display a typically-fractionary "number of hours ago", of course (hour and fraction with some digits, or, round to closest integer number of hours, or what else).

The literal '+0000' in your format, for strptime, means you expect and ignore those literal characters at that spot in your "createdat" string (normally you'd have a timezone offset specifier there). If that's indeed what you want, then you have the right format string!