From: Bill Kelly <billk@...>
Date: 2008-09-20T11:32:42+09:00
Subject: Re: [QUIZ] One-Liners Mashup (#177 again)


From: "Matthew Moss" <matthew.moss@gmail.com>
>
> Ready? Here goes. First problem...
> You should know this pattern well:
> 
>     > [:one, "two", 4] * 3
>     => [:one, "two", 4, :one, "two", 4, :one, "two", 4]
> 
> Write a single line method on Array that does this instead:
> 
>     > [:one, "two", 4].repeat(3)
>     => [:one, :one, :one, "two", "two", "two", 4, 4, 4]


# SOLUTION  1:
# Partial solution, we would need a flatten(1) to prevent it from
# messing up nested arrays like [:one, "two", [3]] -- since flatten
# unarrays recursively.

class Array; def repeat(n); ([self]*n).transpose.flatten; end; end


# SOLUTION 2:
# Avoids flatten, so won't break nested arrays:

class Array; def repeat(n); ([self]*n).transpose.inject([]){|a,e| a += e}; end; end



--------------
NEW CHALLENGE:
--------------

# Given one or more input filenames on the command line, 
# report the number of unique IP addresses found in all the
# data.
#
# (For our purposes, an IP address may simply be considered
# four integerers separated by dots, e.g.: 6.54.123.9 )
#
# Optionally, the solution should read stdin if no filenames
# were specified.
#
# Preferably, the solution should be expressed in the form of
# a ruby command-line invocation. (Optional.)



Regards,

Bill