From: Glenn <glenn_ritz@...>
Date: 2009-01-04T11:29:37+09:00
Subject: Re: Default values of hashes

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Both solutions are great.  I had something else that was sort of working, b=
ut these are far more elegant.=0A=0AThanks!=0A=0A=0A=0A____________________=
____________=0AFrom: "Pe=F1a, Botp" <botp@delmonte-phil.com>=0ATo: ruby-tal=
k ML <ruby-talk@ruby-lang.org>=0ASent: Saturday, January 3, 2009 12:03:35 A=
M=0ASubject: Re: Default values of hashes=0A=0AFrom: Glenn [mailto:glenn_ri=
tz@yahoo.com] =0A# I would be able to add any key to trt_hash and its value=
 =0A# would have a default of an empty hash, and then I'd be able =0A# to a=
dd any element I wanted to the nested hash, and its =0A# default would be 0=
.  But this does not seem to work.=0A# ...I thought if I defined trt_hash l=
ike this:=0A#  trt_hash =3D Hash.new( Hash.new(0))=0A=0Athat is near to you=
r objective. you just have to build the hash since defaults do not, ie use =
the block form to store value in hash http://www.ruby-doc.org/core/classes/=
Hash.src/M002868.html=0A=0Atry eg,=0A=0A> trt_hash =3D Hash.new{|h,k| h[k]=
=3D Hash.new{|h2,k2| h2[k2]=3D0} }=0A=3D> {}=0A> trt_hash["a"]=0A=3D> {}=0A=
> trt_hash=0A=3D> {"a"=3D>{}}=0A> trt_hash["a"][:x]=0A=3D> 0=0A> trt_hash=
=0A=3D> {"a"=3D>{:x=3D>0}}=0A> trt_hash["a"][:x]+=3D100=0A=3D> 100=0A> trt_=
hash=0A=3D> {"a"=3D>{:x=3D>100}}=0A> trt_hash["a"][:x]+=3D100=0A=3D> 200=0A=
> trt_hash=0A=3D> {"a"=3D>{:x=3D>200}}=0A> trt_hash["a"][:w]+=3D100=0A=3D> =
100=0A> trt_hash=0A=3D> {"a"=3D>{:w=3D>100, :x=3D>200}}=0A> trt_hash["b"][:=
w]+=3D100=0A=3D> 100=0A> trt_hash=0A=3D> {"a"=3D>{:w=3D>100, :x=3D>200}, "b=
"=3D>{:w=3D>100}}
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