From: Brett Simmers <bsimmers@...>
Date: 2007-07-21T05:41:49+09:00
Subject: Re: Regexp question

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darren kirby wrote:
> quoth the bcparanj@gmail.com:
>   
>> I have a list of zip codes (3000). Is there any script that I could
>> use to create a regexp for checking if a user entered zip is in this
>> list or not? TIA.
>>     
>
> Doubtful you need a regexp. Answer depends on the format of your list. If it 
> is a separate file with one code per line you could do:
>
> codes = IO.readlines("/path/to/codes").each { |line| line.chomp! }
> codes.include?(90210.to_s)
>
> or if you have ZIP + 4 codes:
>
> codes.include?("90210-1234")
>
> -d
>   
Array#include? is slow for large arrays.  If you'll be performing more 
than 1 lookup over the life of the program, you should create a hash:

codes = Hash.new
IO.readlines("/path/to/codes").each {|code| codes[code.chomp] = true}

Then just test with:
codes['12345']

Or you could use a Set, which basically does the exact same thing with 
different syntax:

require 'set'
codes = Set.new
IO.readlines('/path/to/codes").each {|code| set.add(code.chomp)}

Test with:
set.include?('12345')

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