From: "SHULTZ,BARRY (HP-Israel,ex1)" <barry_shultz@...>
Date: 2001-08-16T14:22:47+09:00
Subject: [ruby-talk:19859] RE:  how to speed up hash script?

Hi,
 
> -----Original Message-----
> From: gerry@ucar.edu [mailto:gerry@ucar.edu]
> Sent: Wednesday, August 15, 2001 8:33 PM

> class Climo
>   def initialize(in_file)
>     # Read in data
>     @fp = File.new(in_file, "r")
>     @lines = @fp.readlines()
>     @fp.close()
>     @num_lines = @lines.size()
>     @date_format = "YYMMDDHH"
>     @len_date = @date_format.size()
>     
>     # Store line indices in dictionary based on date field
>     @dict = Hash.new()
>     for i in 1...@num_lines
>       @dict[@lines[i][0...@len_date]] = i
>     end
>     
>     first_date = @lines[1][0...@len_date]
>     last_date = @lines[@num_lines-1][0...@len_date]
>     puts "first_date: ", first_date
>     puts "last_date: ", last_date
>   end
>   
> 

On my machine this is running slightly faster than 
your script and it's shorter code. If you're willing and able to trade 
your @dict Hash for an Array. At least it makes sense for the piece of code 
you sent. Here I'm trying to take advantage of Enumerable#collect .

 
    @date_format = "YYMMDDHH"
    @len_date = @date_format.size()
    @dict = File.open(in_file,"r").collect{ |line|
      line[0...@len_date]      
  }  
  first_date = @dict[1]
  last_date = @dict[@dict.size - 1]
  puts "first_date: ", first_date
  puts "last_date: ", last_date


My 0.02.
Barry