From: Robert Klemme <shortcutter@...>
Date: 2009-02-10T01:50:27+09:00
Subject: Re: sort_by different variables?

2009/2/9 Taylor Strait <taylorstrait@gmail.com>:
> I have a user control panel that generates an event log by merging
> various things that can happen on the site. These are:
>
> user joins
> user receives invitation
> user completes invitation
> user refers someone
> user referee activates account
>
> So I want to merge these events into a single array and sort them. It
> works well sorting by created_at. However, I do not have unique classes
> for all of the events I want to merge (yeah, REST would have worked well
> here).  So when I populate the array I do this:
>
>      # create array of all events for the log
>      @events = []
>      @events << @user.invitations
>      @events << @user.pending_referrals
>      @events << @user.active_referrals
>      @events = @events.flatten!.sort_by {|x| x.created_at }.reverse

First of all, I believe you want #concat and not #<<:

irb(main):003:0> a = []
=> []
irb(main):004:0> a << [1,2,3]
=> [[1, 2, 3]]
irb(main):005:0> a << [6,7,8]
=> [[1, 2, 3], [6, 7, 8]]
irb(main):006:0> a
=> [[1, 2, 3], [6, 7, 8]]

irb(main):007:0> a = []
=> []
irb(main):008:0> a.concat [1,2,3]
=> [1, 2, 3]
irb(main):009:0> a.concat [6,7,8]
=> [1, 2, 3, 6, 7, 8]
irb(main):010:0> a
=> [1, 2, 3, 6, 7, 8]

> A pending_referral and active_referral are the same object,but pending
> has an activated_at = nil and an active_referral has activated_at =
> datetime.  So, it is possible to sort this array by created_at OR
> activated_at?

arr.sort_by {|x| x.activated_at || x.created_at}

Kind regards

robert

-- 
remember.guy do |as, often| as.you_can - without end