From: don mc <don.mcclean@...>
Date: 2006-07-13T05:59:20+09:00
Subject: Re: multiple level hash assignment equivalence to perl

Thanks! Thats just what I needed.

Regards,
Don

Joel VanderWerf wrote:
> don mc wrote:
>> Is there a succinct way in ruby to do a multiple level hash assignement? 
>> I am more
>> used to perl, which you can do something like
>> 
>> 
>> $hp->{level1}->{level2} = 3
>> 
>> even if the first and second level had never existed below.
> 
> There's an autovivification trick, using the default proc of a hash (see
> ri default_proc):
> 
> irb(main):002:0> pr = proc {|h,k| h[k]=Hash.new(&pr) }
> => #<Proc:0x02c15618@(irb):2>
> irb(main):003:0> h = Hash.new(&pr)
> => {}
> irb(main):004:0> h[1][2][3][4] = 5
> => 5
> irb(main):005:0> h
> => {1=>{2=>{3=>{4=>5}}}}


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