Significantly better. The latter method loads every single model in the queryset into Python, potentially the whole database! On May 15, 2013 9:24 PM, "Lee Trout" <[email protected]> wrote:
> Is qs[:1][0] better form than list(qs)[0]? > > > On Wed, May 15, 2013 at 7:48 AM, Selwin Ong <[email protected]> wrote: > >> I've updated the first() and last() to not accept any arguments. Please >> review it and let me know if there's anything else I need to change. >> Hopefully this can get merged in during the sprints and make it into 1.6 :). >> >> The pull request is here: https://github.com/django/django/pull/1056 >> >> Best, >> Selwin >> >> On Monday, May 13, 2013 8:12:35 PM UTC+7, Michal Petrucha wrote: >>> >>> > > I initially modeled "first()" and "last()"'s behaviors to mimic >>> > > "latest()", but in this new pull request, you can pass multiple >>> field names >>> > > into "first()" and "last()" so it behaves like "order_by()". It's >>> more >>> > > flexible and requires less typing, but I wonder if we should just >>> get rid >>> > > of the optional field arguments and rely on "order_by" for ordering. >>> "There >>> > > should be one-- and preferably only one --obvious way to do it". >>> > >>> > Considering "There should be one-- and preferably only one --obvious >>> way to >>> > do it", I definitely prefer to rely on order_by to do the ordering, >>> not on >>> > first. >>> > >>> > .order_by('name').first() >>> > >>> > is clear and readable in my opinion. >>> >>> My thoughts exactly, we already have one method that does ordering, I >>> don't think it is necessary to make these methods incorporate that >>> functionality. If we did, we might argue that other QuerySet >>> operations could be supported as well and that would just result in a >>> bloated API. Especially if there's no performance gain (the QuerySet >>> would be cloned anyway), and it only saves a few lines of code. >>> >>> Also, skimming through this thread, I think there was a consensus on >>> first() and last() not taking any ordering arguments, i.e. the first >>> proposed syntax: >>> >>> .filter(last_name__startswith=**'b').order_by('last_name').**first() >>> >>> >>> Michal >>> >> -- >> You received this message because you are subscribed to the Google Groups >> "Django developers" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to [email protected]. >> To post to this group, send email to [email protected]. >> Visit this group at >> http://groups.google.com/group/django-developers?hl=en. >> For more options, visit https://groups.google.com/groups/opt_out. >> >> >> > > -- > You received this message because you are subscribed to the Google Groups > "Django developers" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To post to this group, send email to [email protected]. > Visit this group at http://groups.google.com/group/django-developers?hl=en > . > For more options, visit https://groups.google.com/groups/opt_out. > > > -- You received this message because you are subscribed to the Google Groups "Django developers" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/django-developers?hl=en. For more options, visit https://groups.google.com/groups/opt_out.
