From: Matthew Kerwin <matthew@...>
Date: 2013-02-05T11:23:23+09:00
Subject: Re: How to increase flexibility of #flatten

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On 5 February 2013 11:03, Tom Stut <lists@ruby-forum.com> wrote:

> I am trying to use flatten to change
>
> #this
> => [ [1, 3], [1, 4], [2, 3], [2, 4], [ [5, 5], [6, 6] ] ]
> #to this.
> => [ [1,3], [1,4], [2,3], [2,4], [5,5], [6,6] ]
>
> I've tried giving flatten an argument of 1, but it removes dimensions
> that I want to remain.
>
> >> x.flatten(1)
> => [1, 3, 1, 4, 2, 3, 2, 4, [5, 5], [6, 6] ]
>
> is there a way to iterate through that first array to produce the output
> I want using flatten?
>

Do you want a general solution that will always reduce things down the the
inner-most array?  And is there no limit to how many levels deep those
inner-most arrays will be?  If so, you'd probably need a recursive function
call.

Note that if all the inner-most arrays have exactly two elements, you can
use:
    my_array.flatten.each_slice(2).to_a

(the .to_a is to collapse the Enumerator back to actual data; not really
necessary most of the time)

-- 
  Matthew Kerwin, B.Sc (CompSci) (Hons)
  http://matthew.kerwin.net.au/
  ABN: 59-013-727-651

  "You'll never find a programming language that frees
  you from the burden of clarifying your ideas." - xkcd

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<div dir=3D"ltr"><div class=3D"gmail_extra">On 5 February 2013 11:03, Tom S=
tut <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><div class=3D"gmail_=
quote"><blockquote class=3D"gmail_quote" style=3D"margin:0px 0px 0px 0.8ex;=
border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:=
solid;padding-left:1ex">
I am trying to use flatten to change<br>
<br>
#this<br>
=3D&gt; [ [1, 3], [1, 4], [2, 3], [2, 4], [ [5, 5], [6, 6] ] ]<br>
#to this.<br>
=3D&gt; [ [1,3], [1,4], [2,3], [2,4], [5,5], [6,6] ]<br>
<br>
I&#39;ve tried giving flatten an argument of 1, but it removes dimensions<b=
r>
that I want to remain.<br>
<br>
&gt;&gt; x.flatten(1)<br>
=3D&gt; [1, 3, 1, 4, 2, 3, 2, 4, [5, 5], [6, 6] ]<br>
<br>
is there a way to iterate through that first array to produce the output<br=
>
I want using flatten?<br></blockquote></div><div class=3D"gmail_extra"><br>=
</div>Do you want a general solution that will always reduce things down th=
e the inner-most array? =A0And is there no limit to how many levels deep th=
ose inner-most arrays will be? =A0If so, you&#39;d probably need a recursiv=
e function call.<div>
<br></div><div>Note that if all the inner-most arrays have exactly two elem=
ents, you can use:</div><div>=A0 =A0 my_array.flatten.each_slice(2).to_a</d=
iv><div><br></div><div style>(the .to_a is to collapse the Enumerator back =
to actual data; not really necessary most of the time)</div>
<div><br></div>-- <br>=A0 Matthew Kerwin, B.Sc (CompSci) (Hons)<br>=A0 <a h=
ref=3D"http://matthew.kerwin.net.au/" target=3D"_blank">http://matthew.kerw=
in.net.au/</a><br>=A0 ABN: 59-013-727-651<br><br>=A0 &quot;You&#39;ll never=
 find a programming language that frees<br>
=A0 you from the burden of clarifying your ideas.&quot; - xkcd
</div></div>

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