From: Summercool <Summercoolness@...>
Date: 2007-09-16T10:30:30+09:00
Subject: Re: Newbie help



On Sep 15, 5:16 pm, Ali Koubeissi <ali.koubei...@hotmail.com> wrote:
> Hey, I've started with Ruby two days ago, and I have some questions.
>
> 1- What's the use of Symbols? I've read that symbols are (Symbols are
> lightweight strings. Usually, symbols are used in situations where you
> need a string but you won't be printing it to the screen.), however I
> cannot understand how to use them, and so I tried to read some examples
> and I got this:

here are two tests:

-------------- symbol_vs_string.rb
--------------------------------------

i = 0
n = 10000000
hash = {}

hash["foobarfoobarfoobarfoobarfoobarfoobarfoobarfoobarfoobarfoobar"] =
0

start_time = Time.now

while i < n
  hash["foobarfoobarfoobarfoobarfoobarfoobarfoobarfoobarfoobarfoobar"]
+= 1
  i += 1
end

finish_time = Time.now

puts
hash["foobarfoobarfoobarfoobarfoobarfoobarfoobarfoobarfoobarfoobar"]



puts
puts "It took #{finish_time - start_time} seconds to run. #{(n /
(finish_time - start_time)).to_i} iterations per second."



-------------- symbol_vs_string2.rb
--------------------------------------

i = 0
n = 10000000
hash = {}

hash[:foobarfoobarfoobarfoobarfoobarfoobarfoobarfoobarfoobarfoobar] =
0

start_time = Time.now

while i < n
  hash[:foobarfoobarfoobarfoobarfoobarfoobarfoobarfoobarfoobarfoobar]
+= 1
  i += 1
end

finish_time = Time.now

puts
hash[:foobarfoobarfoobarfoobarfoobarfoobarfoobarfoobarfoobarfoobar]



puts
puts "It took #{finish_time - start_time} seconds to run. #{(n /
(finish_time - start_time)).to_i} iterations per second."





C:\rails\depot>ruby symbol_vs_string.rb
10000000

It took 30.703 seconds to run. 325701 iterations per second.

C:\rails\depot>ruby symbol_vs_string2.rb
10000000

It took 11.984 seconds to run. 834445 iterations per second.

C:\rails\depot>ruby symbol_vs_string2.rb

It took 11.922 seconds to run. 838785 iterations per second.

C:\rails\depot>ruby symbol_vs_string.rb
10000000

It took 30.391 seconds to run. 329044 iterations per second.