From: Matt Williams <matt@...>
Date: 2009-02-13T02:22:22+09:00
Subject: Re: Arrays and Hashes processing :pls help

On Fri, 2009-02-13 at 01:58 +0900, Jags Rao wrote:
> 
> hi friends
> 
> i have a long array with structure like this
> 
> [["377", "838"],
>  ["377", "990"],
>  ["377", "991"],
>  ["377", "992"],
>  ["378", "840"],
>  ["378", "841"],
>  ["378", "842"],
>  ["378", "843"],
>  ["378", "844"]]
> 
> how can i convert it in one line to
> 
> [["377", "838 990 991 992"],
>  ["378", "840 841 842 843 844"]]



> if thats diificult is the below array processable in one line
> 
> [{"prefix"=>"838", "scf_id"=>"377"},
>  {"prefix"=>"990", "scf_id"=>"377"},
>  {"prefix"=>"991", "scf_id"=>"377"},
>  {"prefix"=>"992", "scf_id"=>"377"},
>  {"prefix"=>"840", "scf_id"=>"378"},
>  {"prefix"=>"841", "scf_id"=>"378"},
>  {"prefix"=>"842", "scf_id"=>"378"},
>  {"prefix"=>"843", "scf_id"=>"378"},
>  {"prefix"=>"844", "scf_id"=>"378"}]
> 
> in this form
> 
> [{"prefix"=>"838 990 991 992", "scf_id"=>"377"},
>  {"prefix"=>"840 841 842 843 844", "scf_id"=>"378"}]
> 


I don't understand the need for one line, but....  Also, why an array of
hashes?  why not a hash?

if your array of hashes is referenced by h, then:
out = h.inject({}) {|s,v| x=s[v["scf_id"]] || ""; s[v["scf_id"]]="#{x}
#{v["prefix"]}".trim;s}

that (above) gives you a hash with distinct values of scf_id referencing
prefixes.  That said, you can do the following if you *must* have an
array:
out = (h.inject({}) {|s,v| x=s[v["scf_id"]] || ""; s[v["scf_id"]]="#{x}
#{v["prefix"]}".trim;s}).inject([]){|s,v|
s<<{"scf_id"=>v[0],"prefix"=>v[1]};s}

It's ugly.  Not maintainable.

Why the need for one line?


> pls help
> Jags