From: Logan Capaldo <logancapaldo@...>
Date: 2007-08-07T10:47:23+09:00
Subject: Re: Determining the common prefix for several strings

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On 8/6/07, Xavier Noria <fxn@hashref.com> wrote:
>
> El Aug 6, 2007, a las 5:13 PM, Stefan Rusterholz escribi=F3:
>
> > Wow, I'm surprised nobody had the idea of simply using Array#abbrev,
> > which is included in the stdlib.
>
> There's no guarantee you can obtain the maximum common prefix from
> its output, because it computes _unambiguous_ prefixes:
>
>    %w{ item1 item2 }.abbrev
>    =3D> {"item1"=3D>"item1", "item2"=3D>"item2"}
>
> See, no "item" there, you end up basically with the information you
> had before the call.



irb(main):027:0>    items =3D [
irb(main):028:1*     'item001',
irb(main):029:1*     'item004',
irb(main):030:1*     'item002',
irb(main):031:1*     'item002b',
irb(main):032:1*     'item002C',
irb(main):033:1*     'item 5',
irb(main):034:1*     'item 10',
irb(main):035:1*     'itemize this'
irb(main):036:1>   ]
irb(main):039:0> Abbrev.abbrev(items).sort_by { |s,| s.length}.first.first[=
0..-
2]
=3D> "item"
irb(main):040:0> items =3D ["happy", "happening", "hapless"]
=3D> ["happy", "happening", "hapless"]
irb(main):041:0> Abbrev.abbrev(items).sort_by { |s,| s.length}.first.first[=
0..-
2]
=3D> "hap"
irb(main):042:0> items =3D ["c", "b", "a"]
=3D> ["c", "b", "a"]
irb(main):043:0> Abbrev.abbrev(items).sort_by { |s,| s.length}.first.first[=
0..-
2]
=3D> ""
irb(main):044:0>

I've edited out some false starts. Please feel free to point out any flaws
that I've missed

Abbrev.abbrev(items).sort_by { |s,| s.length }.first.first[0..-2]


>

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