From: 7stud -- <lists@...>
Date: 2012-10-02T12:37:56+09:00
Subject: Re: how to read arrary with an array

> don't undestand chap [0] and chap [1] reference

If you are confused, it is the author's fault for choosing confusing 
variable names.  If the variable names were descriptive, the code would 
be self explanatory.


colors = ['red', 'black', 'yellow']

colors.each do |color|
  puts "The current color is: #{color}"
end

--output:--
The current color is: red
The current color is: black
The current color is: yellow


array_of_arrays = [
  [10, 20, 30],
  ['a', 'b', 'c', 'd'],
  ['hello', 'goodbye']
]

array_of_arrays.each do |sub_array|
  p sub_array
end

--output:--
[10, 20, 30]
["a", "b", "c", "d"]
["hello", "goodbye"]


array_of_arrays.each do |sub_array|
  puts sub_array[0]
end

--output:--
10
a
hello


array_of_arrays.each do |chapter|
  puts chapter[0]
end

--output:--
10
a
hello


zebras = [
  [10, 20, 30],
  ['a', 'b', 'c', 'd'],
  ['hello', 'goodbye']
]

zebras.each do |elephant|
  p elephant[0]
end

--output:--
10
"a"
"hello"


If you are confused about what is contained in a variable, go ahead and 
print it out, e.g.

zebras.each do |elephant|  #what the #@$#@ is elephant referring to??
  p elephant   #add this line to see what the heck elephant is all about
  p elephant[0]
end

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