From: "Kroeger, Simon (ext)" <simon.kroeger.ext@...>
Date: 2006-04-20T18:35:07+09:00
Subject: Re: Write Out Then Read In Hash of Two-element Arrays

Well,

your primary problem is that you write both elements of the
arrays on separat lines. When reading you will read more
lines than you expect (twice as much to be correct).

So an easy fix would be to write using 

  fileOut.puts histHash[i].join(',')

so both values are on the same line.
If you read them in you have to split the line to get two
distinct values again.

  fileIn.each_line{|line|histHash[i]= line.split(',').map{|s| s.to_i}}

that said, I would recommend having a close look at yaml.

cheers

Simon

> -----Original Message-----
> From: list-bounce@example.com 
> [mailto:list-bounce@example.com] On Behalf Of David Bailey
> Sent: Thursday, April 20, 2006 11:01 AM
> To: ruby-talk ML
> 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
> 
> 
> -- 
> Posted via http://www.ruby-forum.com/.
> 
>