From: Rob Biedenharn <Rob@...>
Date: 2009-05-19T00:37:57+09:00
Subject: Re: Sorting numbers as strings


On May 18, 2009, at 10:40 AM, Robert Klemme wrote:

> 2009/5/18 Jack Bauer <realmadrid2727@yahoo.es>:
>> I'm trying to sort some strings containing numbers. The strings
>> themselves can't be changed (they're items being pulled from a DB.)  
>> This
>> is an example of some of the things I need to sort. First is how I
>> wanted them sorted:
>>
>> FastEthernet0/1
>> FastEthernet0/10
>> FastEthernet0/11
>> FastEthernet0/12
>> FastEthernet0/13
>> FastEthernet0/2
>> FastEthernet0/3
>> FastEthernet0/4
>> FastEthernet0/5
>> FastEthernet0/6
>> FastEthernet0/7
>> FastEthernet0/8
>> FastEthernet0/9
>> ...
>>
>> I need to get it like this:
>> FastEthernet0/1
>> FastEthernet0/2
>> FastEthernet0/3
>> FastEthernet0/4
>> FastEthernet0/5
>> FastEthernet0/6
>> FastEthernet0/7
>> FastEthernet0/8
>> FastEthernet0/9
>> FastEthernet0/10
>> FastEthernet0/11
>> FastEthernet0/12
>> FastEthernet0/13
>>
>> Then they could turn into FastEthernet1/1, etc. Also, the name  
>> doesn't
>> really matter as it could have FastEthernet, another name, or none at
>> all and just be 0/1 or whatever.
>>
>> I'm guessing something like a regex to strip non-numbers so
>> FastEthernet0/1 becomes 01 then sort numerically, but that wouldn't  
>> help
>> if I have FastEthernet0/1, GigabitEthernet0/1, and FastEthernet0/2  
>> since
>> it would come out in an incorrect order (01, 01, 02 instead of 01,  
>> 02,
>> 01 because of the F and G alphabetical sort.)
>>
>> Any ideas of the best way to go about this?
>
> 16:40:24 Temp$ cat srt.rb
> puts DATA.sort_by {|s| s.scan(/\d+/).map {|x| x.to_i} }
<snip/>
>
> Kind regards
>
> robert
> -- 
> remember.guy do |as, often| as.you_can - without end
> http://blog.rubybestpractices.com/

If you do need to consider things like "FastEthernet..." v.  
"GigabitEthernet...", then perhaps you want something like this which  
breaks the original string into digits and non-digits and converts the  
digits to be integers.

puts DATA.sort_by {|s| s.scan(/\d+|\D+/).map {|x| x =~ /\d+/ ?  
x.to_i : x } }

-Rob

Rob Biedenharn		http://agileconsultingllc.com
Rob@AgileConsultingLLC.com