From: Rob Biedenharn <Rob@...>
Date: 2009-06-02T11:29:14+09:00
Subject: Re: Ruby enhancement suggestion


On Jun 1, 2009, at 10:01 PM, Steve Hull wrote:

> Joel VanderWerf wrote:
>>   p h.map{|pair| pair.join("=>")}.join(",")
>
> That is indeed nice and compact.  Thanks Joel!!  That'll do quite  
> nicely
> for my needs.   :)
>
> Daniel Berger wrote:
>> require 'pp'
>> pp hash
>
> Thanks Dan!  That's a cool feature, but not really what I'm looking  
> for
> in the hash.join idea.  It is indeed something I'll be using in the
> future though.  :)
> --


Before the other replies, I was thinking that you just wanted  
Hash#inspect

irb> hash = {}
=> {}
irb> (0..20).each {|i| hash[i] = i+1 }
=> 0..20
irb> hash
=> {16=>17, 5=>6, 11=>12, 0=>1, 17=>18, 6=>7, 12=>13, 1=>2, 18=>19,  
7=>8, 13=>14, 2=>3, 19=>20, 8=>9, 14=>15, 3=>4, 20=>21, 9=>10, 15=>16,  
4=>5, 10=>11}
irb> puts hash.inspect
{16=>17, 5=>6, 11=>12, 0=>1, 17=>18, 6=>7, 12=>13, 1=>2, 18=>19, 7=>8,  
13=>14, 2=>3, 19=>20, 8=>9, 14=>15, 3=>4, 20=>21, 9=>10, 15=>16, 4=>5,  
10=>11}
=> nil
irb> hash.inspect
=> "{16=>17, 5=>6, 11=>12, 0=>1, 17=>18, 6=>7, 12=>13, 1=>2, 18=>19,  
7=>8, 13=>14, 2=>3, 19=>20, 8=>9, 14=>15, 3=>4, 20=>21, 9=>10, 15=>16,  
4=>5, 10=>11}"

It even keeps the type of the key straight for you.

irb> {:sym => "I'm a symbol", 'string' => "String here!", 1 =>  
'Fixnum, too'}.inspect
=> "{1=>\"Fixnum, too\", :sym=>\"I'm a symbol\", \"string\"=>\"String  
here!\"}"

Of course, you could manage that yourself, too, easily enough with  
something close to what Joel said:

irb> class Hash
irb>     def join(key_value_sep="=>", pair_sep=",")
irb>         map{|k,v|  
[k.inspect,v.inspect].join(key_value_sep)}.join(pair_sep)
irb>       end
irb>   end
=> nil
irb> puts hash.join(" says ", ",\n ")
16 says 17,
  5 says 6,
  11 says 12,
  0 says 1,
  17 says 18,
  6 says 7,
  12 says 13,
  1 says 2,
  18 says 19,
  7 says 8,
  13 says 14,
  2 says 3,
  19 says 20,
  8 says 9,
  14 says 15,
  3 says 4,
  20 says 21,
  9 says 10,
  15 says 16,
  4 says 5,
  10 says 11
=> nil

Note that #inspect is "smarter" because the individual keys and values  
can do what is right for them.  Try the simple #join varieties with  
values that are themselves Hashes or Arrays.

-Rob

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