From: David Bailey <david.bailey@...>
Date: 2006-04-20T18:00:32+09:00
Subject: Write Out Then Read In Hash of Two-element Arrays

Kind All,

I wonder if one of you knowledgeble folks can steer me in he right 
direction:

I'm trying to get a hash I've created read back in after after writing 
it out to a file, so that it is exactly the same afterward.  The hash 
has zero-based integer keys and two-element array values.

After I create and populate the hash:
Length of histHash after creation = 5

When I write out the hash, the output to STDOUT looks like this:
Write histHash[0] = 101
Write histHash[1] = 112
Write histHash[2] = 123
Write histHash[3] = 134
Write histHash[4] = 145
5 histHash lines written
histHash written = 01011112212331344145

After I delete the elements of the hash:
Length of histHash after deletion = 0

But when I read it back in, it looks like this:
Read histHash[0] = 10;  line = 10
Read histHash[1] = 1;  line = 1
Read histHash[2] = 11;  line = 11
Read histHash[3] = 2;  line = 2
Read histHash[4] = 12;  line = 12
Read histHash[5] = 3;  line = 3
Read histHash[6] = 13;  line = 13
Read histHash[7] = 4;  line = 4
Read histHash[8] = 14;  line = 14
Read histHash[9] = 5;  line = 5
10 histHash lines read
histHash read = 5301061311742118143295412
Length of histHash after read = 10

As you can see, it's length is five lines when I initially write it to 
the file, but ten lines when I read it back in.  I've been pawing though 
the docs, but I can't figure out what I'm doing wrong.  Any help will be 
greatly appreciated.

Here is the errant code:
#  write out and then read in hash of two-element arrays
#  create and populate the hash
histHash = Hash.new
histHash[0] = [10, 1]
histHash[1] = [11, 2]
histHash[2] = [12, 3]
histHash[3] = [13, 4]
histHash[4] = [14, 5]
puts
puts "Length of histHash after creation = #{histHash.length}"
puts

#  write the hash to the file
fileOut = File.new("savedHash.sdo", "w")
histHash.length.times do |i|
  fileOut.puts(histHash[i])
  puts "Write histHash[#{i}] = #{histHash[i]}"
end
fileOut.close

puts "#{histHash.length} histHash lines written"
puts "histHash written = #{histHash}"
puts

#  Delete the hist hash elements
histHash.length.times do |i|
  histHash.delete(i)
end
puts "Length of histHash after deletion = #{histHash.length}"
puts

#  load (read) the saved file
fileIn = File.new("savedHash.sdo", "r")
i = 0
fileIn.each_line{|line|histHash[i]=[line.to_i]; puts "Read 
histHash[#{i}] = #{histHash[i]};  line = #{line}";i+=1}
fileIn.close
puts "#{histHash.length} histHash lines read"
puts "histHash read = #{histHash}"
puts "Length of histHash after read = #{histHash.length}"
puts


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