From: "Peña, Botp" <botp@...>
Date: 2007-08-07T11:26:18+09:00
Subject: Re: Determining the common prefix for several strings

From: Logan Capaldo [mailto:logancapaldo@gmail.com] 
# 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]

I cannot prove it wrong, hacker Logan :)

i just put some cosmetics though by getting the extract fr min,

irb(main):099:0> list=[
irb(main):100:1* "item two of those",
irb(main):101:1* "item two",
irb(main):102:1* "item1",
irb(main):103:1* "item22",
irb(main):104:1* "item333",
irb(main):105:1* "item 444",
irb(main):106:1* "item 5555",
irb(main):107:1* "item6a",
irb(main):108:1* "item6b",
irb(main):109:1* "item---x",
irb(main):110:1* "itemy",
irb(main):111:1* "item whatever :)",
irb(main):112:1* ]
=> ["item two of those", "item two", "item1", "item22", "item333", "item 444", "item 5555", "item6a", "item6b", "item---x", "itemy", "item whatever :)"]
irb(main):113:0> list.abbrev.min{|(a1,),(b1,)|a1.length<=>b1.length}.first[0..-2]
=> "item"

so, 
  list.abbrev.min{|(a1,),(b1,)|a1.length<=>b1.length}.first[0..-2]

your magic number "0..2" is an amazingly simple hack (it looks like 42 :). but i'm not sure how this abbrev scheme stands stands against the regex solutions though.

kind regards -botp