From: Robert Klemme <shortcutter@...>
Date: 2013-06-18T02:57:01+09:00
Subject: Re: Compare and sort one array according to another.

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On Mon, Jun 17, 2013 at 5:43 PM, masta Blasta <lists@ruby-forum.com> wrote:

> I have two arrays of objects that look something like this:
>
> arr1 = [
> Obj1(prop1, prop2, id),
> Obj2(prop1, prop2, id),
> Obj3(prop1, prop2, id)
> ]
>
> arr2 = [
> OthrObj1(prop1, prop2, ref_id),
> OthrObj2(prop1, prop2, ref_id),
> OthrObj3(prop1, prop2, ref_id)
> ]
>
> The objects in arr1 are ordered by id (just as an example). The
> objects in arr2 have a 1-1 relationship with the objects in arr1,
> however they are not sorted. They need to be sorted to match the order
> of the objects in arr1. The order of arr1 is not predictable so arr2 has
> to be compared to arr1 to find the order. The two arrays are always the
> same size. No items should repeat, however this might be something i
> need to guard against. For now let's assume no items repeat.
>
> My current solution is to make a temp array and then build it with the
> items in order. It's ok but i'm wondering if there's a better ruby
> method.
>


Something like this?

arr2.sort_by {|o| arr1.find_index {|a| o.prop1 == a.prop1 && o.prop2 ==
a.prop2}}

Kind regards

robert


-- 
remember.guy do |as, often| as.you_can - without end
http://blog.rubybestpractices.com/

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<div dir=3D"ltr"><br><div class=3D"gmail_extra"><br><br><div class=3D"gmail=
_quote">On Mon, Jun 17, 2013 at 5:43 PM, masta Blasta <span dir=3D"ltr">&lt=
;<a href=3D"mailto:lists@ruby-forum.com" target=3D"_blank">lists@ruby-forum=
.com</a>&gt;</span> wrote:<br>
<blockquote class=3D"gmail_quote" style=3D"margin:0 0 0 .8ex;border-left:1p=
x #ccc solid;padding-left:1ex">I have two arrays of objects that look somet=
hing like this:<br>
<br>
arr1 =3D [<br>
Obj1(prop1, prop2, id),<br>
Obj2(prop1, prop2, id),<br>
Obj3(prop1, prop2, id)<br>
]<br>
<br>
arr2 =3D [<br>
OthrObj1(prop1, prop2, ref_id),<br>
OthrObj2(prop1, prop2, ref_id),<br>
OthrObj3(prop1, prop2, ref_id)<br>
]<br>
<br>
The objects in arr1 are ordered by id (just as an example). The<br>
objects in arr2 have a 1-1 relationship with the objects in arr1,<br>
however they are not sorted. They need to be sorted to match the order<br>
of the objects in arr1. The order of arr1 is not predictable so arr2 has<br=
>
to be compared to arr1 to find the order. The two arrays are always the<br>
same size. No items should repeat, however this might be something i<br>
need to guard against. For now let&#39;s assume no items repeat.<br>
<br>
My current solution is to make a temp array and then build it with the<br>
items in order. It&#39;s ok but i&#39;m wondering if there&#39;s a better r=
uby<br>
method.<br>
</blockquote><div>=A0</div><div>=A0</div></div>Something like this?</div><d=
iv class=3D"gmail_extra"><br>arr2.sort_by {|o| arr1.find_index {|a| o.prop1=
 =3D=3D a.prop1 &amp;&amp; o.prop2 =3D=3D a.prop2}}</div><div class=3D"gmai=
l_extra"><br>
</div><div class=3D"gmail_extra" style>Kind regards</div><div class=3D"gmai=
l_extra" style><br></div><div class=3D"gmail_extra" style>robert</div><div =
class=3D"gmail_extra"><br><div><br></div>-- <br>remember.guy do |as, often|=
 as.you_can - without end<br>
<a href=3D"http://blog.rubybestpractices.com/">http://blog.rubybestpractice=
s.com/</a>
</div></div>

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