```"Ruby Quiz" <james / grayproductions.net> wrote in message > The three rules
of Ruby Quiz:
>
> by Morton Goldberg
>
> Your mission is to pick a word list in some language (it will have be one
> that
> uses roman letters) and write Ruby code to filter the list to extract all
> the
> words which are valid numbers in a given base. For many bases this isn't
> an
> interesting task--for bases 2-10, the filter comes up empty; for bases
> 11-13,
> the filter output is uninteresting (IMO); for bases approaching 36, the
> filter
> passes almost everything (also uninteresting IMO). However, for bases in
> the
> range from 14 to about 22, the results can be interesting and even
> surprising,
> especially if one constrains the filter to accept only words of some
> length.
>
Here are my 4 solutions :) (all use ?, so they will not work in 1.9)

# solution #1 - Simple one-liner

%r"^[a-#{(?a-11+ARGV[1].to_i).chr}]+\$"}.sort_by{|w| [w.length,w]} if
(?a...?z)===?a-11+ARGV[1].to_i

# solution #2 - Non-hackery substs, like Olaf

%r"^[a-#{(?a-11+ARGV[1].to_i).chr}|lO]+\$"}.sort_by{|w| [w.length,w]} if
(?a...?k)===?a-11+ARGV[1].to_i

# solution #3 - c001 hackerz

%r"^[a-#{(?a-11+ARGV[1].to_i).chr}|lo]+\$"i}.map{|w|
w.downcase.gsub('o','0').gsub('l','1')}.sort_by{|w| [w.length,w]} if
(?a...?k)===?a-11+ARGV[1].to_i

# solution #4 - B16 5H0UT1N6 HACKER2

base=ARGV[1].to_i
base_=base+?a-11

raise "Bad base: [#{base}]" if base<1  || base_>?z

sub0=base_ < ?o
sub1=base>1 && base_ < ?l
sub2=base>2 && base_ < ?z
sub5=base>5 && base_ < ?s
sub6=base>6 && base_ < ?g
sub8=base>8 && base_ < ?b

reg="^["
reg<<'O' if sub0
reg<<'I' if sub1
reg<<'Z' if sub2
reg<<'S' if sub5
reg<<'G' if sub6
reg<<'B' if sub8
reg<<"|a-#{base_.chr}" if base>10
reg<<']+\$'

w.upcase}.sort_by{|w| [w.length,w]}
result.map!{|w| w.gsub('O','0')} if sub0
result.map!{|w| w.gsub('I','1')} if sub1
result.map!{|w| w.gsub('Z','2')} if sub2
result.map!{|w| w.gsub('S','5')} if sub5
result.map!{|w| w.gsub('G','6')} if sub6
result.map!{|w| w.gsub('B','8')} if sub8
result.reject!{|w| w !~ /[A-Z]/} # NUM8ER5-0NLY LIKE 61885 ARE N0T READA8LE
p result

```