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To: python-list@python.org
From: Mark Lawrence <breamoreboy@yahoo.co.uk>
Subject: Re: simpler increment of time values?
Date: Thu, 05 Jul 2012 03:35:29 +0100
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On 05/07/2012 01:29, Vlastimil Brom wrote:
> Hi all,
> I'd like to ask about the possibilities to do some basic manipulation
> on timestamps - such as incrementing a given time (hour.minute -
> string) by some minutes.
> Very basic notion of "time" is assumed, i.e. dateless,
> timezone-unaware, DST-less etc.
> I first thought, it would be possible to just add a timedelta to a
> time object, but, it doesn't seem to be the case.
>
> The code I came up with (using time and datetime modules) seems rather
> convoluted and I would like to ask about some possible more
> straightforward alternatives I missed.
> The equivalent function (lacking validation) without the (date)time
> libraries seems simple enough (for this limited and individual task).
> Although it is probably mostly throw-away code, which seems to do what
> I need, I'd be interested in better/more elegant... solutions.
>
> # # #
> import time
> import datetime
> import re
>
> print re.sub(r"^0","", (datetime.datetime(*list(time.strptime("8.45",
> "%H.%M"))[:6]) + datetime.timedelta(minutes=30)).strftime("%H.%M"))
> # 9.15
>
> # # # # # # # # #
>
> def add_minutes(hour_min_str, separator=".", minutes_to_add=0):
>      h, m = [int(s) for s in hour_min_str.split(separator)]
>      sum_minutes = h * 60 + m + minutes_to_add
>      h, m = divmod(sum_minutes, 60)
>      h = h % 24
>      return "%s%s%s" % (h, separator, m)
>
> print add_minutes(hour_min_str="8.45", separator='.', minutes_to_add=30)
> # 9.15
>
> # # # # # # # # #
>
> Is it true, that timedelta cannot be used with dateless time values?
> (Is there some other possibility than the current one, where strptime
> actually infers 1. 1. 1900?)
> Is there some simpler way to adapt the incompatible output of strptime
> as the input of datetime?
> Is it possible to get one-digit hours formatted without the leading zero?
>
> Thanks in advance for any suggestions or remarks;
>             regards,
>                Vlastimil Brom
>

from dateutil.relativedelta import relativedelta should simplify things 
for you

google and ye shall find :)

-- 
Cheers.

Mark Lawrence.