From: kinfe0@... (Kinfe)
Date: 2002-01-07T02:36:14+09:00
Subject: [ruby-talk:30355] Re: move index back ward in list.each do {}

Yohanes Santoso <ysantoso@jenny-gnome.dyndns.org> wrote in message news:<87vgegxlcm.fsf@jenny-gnome.dyndns.org>...
> >    At this point I would like to advance the next index in a.each but
> > remain in b.each, another word, b[4] will not become b[5] after the
> > a[had advance], how can I do ?
> 
> I can't really understand your example (including the one in your
> latter posting about cows and pigs). But I got what you mean, I think.
> 
> How about this then:
> 
> a=[1,2,3,4,5]
> b=[5,4,3,2,1]
> next_i = false
> a.each do |i|
>   puts "i=#{i}"
>   if next_i
>     next_i = false
>     next 
>   end
>   b.each do |j|
>     if i==j
>       puts "Advance i to #{i+1}, keep j at #{j}"
>       i += 1
>       next_i = true
>       redo
>     end
>     puts "i=#{i}\tj=#{j}"
>   end
> end
> 
> The output for the above follows after my signature. 
> 
> In all honesty, the above is ugly and confusing. How about using
> nested while? That will allow a much finer control, shorter code, and
> makes a clearer point because, at least for me, if I see a nested
> each, I do not expect for the inner each to control the outer
> each.
> 
> YS.
> 
> i=1
> i=1	j=5
> i=1	j=4
> i=1	j=3
> i=1	j=2
> Advance i to 2, keep j at 1
> i=2	j=1
> i=2
> i=3
> i=3	j=5
> i=3	j=4
> Advance i to 4, keep j at 3
> i=4	j=3
> i=4	j=2
> i=4	j=1
> i=4
> i=5
> Advance i to 6, keep j at 5
> i=6	j=5
> i=6	j=4
> i=6	j=3
> i=6	j=2
> i=6	j=1


This may be too much for me at this point of learning Ruby. Anyway,
the data isn't all numeric, they are lines of records reading into
array cow, pig.

format is

type weight date origin

cow 100 010502 kansas
cow 300 010102 ohio
cow 200 010101 newyork
more
pig 600 010101 somewhere
pig 100 010101 mexico
pig 400 010102 virginia
pig 500 010202 california
more

many more of these with different weight, my real goal is to match the
weight pair until they are equal, so if the pig's weight is 600
pounds, and the cow is  100 then I want to subtract  pig_remain =
pig(600) - cow(100) , so I will want to keep reading in the cow loop
but not the pig loop and repeat the process of subtraction until the
weight is equal . This is of I have done.

cow.each do |c|
 a=cow.split
 pig.each do |p|
  b=split.pig
  if (b[1] >= a[1])
    pig_remain = b[1] - a[1]
    #
    #and get out of here to cow loop to fetch another record and do
the
    #subtraction until they equal before fetching another pig.each |p|
    #
    # If I could move the pig.each |p| back one position then it
should give me
    # what I want, right?
    break
   end
  end
end