From: Zundra Daniel <zundra.daniel@...>
Date: 2010-07-10T13:38:21+09:00
Subject: Re: if statements and case statements questions

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Case statements are not faster.  Both Case and if statements are constant
time operations so there is no speed benefit of one over the other.  It
really just comes down to your preference in any given situation.  Depending
on the code one or the other can lead to cleaner and easier to understand
code.

Oh and cool name btw :-)

On Sat, Jul 10, 2010 at 12:30 AM, John Crichton <a2533488@bofthew.com>wrote:

> I am fairly new to Ruby and programming and had a couple questions about
> if/else and case statements.  I was wondering if there were benefits to
> using case statements instead of if/elsif/else type statements.  Are
> case statements faster?
>
> If I am reading in a file line by line and doing something similar to
>
> lines = File.open("file.csv")
> FasterCSV.parse(lines) do |row|
>  if ( lines =~ /^blah/)
>
>    puts "blahblahblah"
>    some_method
>  end
>
>  if ( lines =~ /^name/ && row[1] =="123")
>    puts "ping pong abc"
>    another_method
>  end
>  if ( lines =~ /^address/ && row[3] =="XYZ")
>    puts "abcdefghijklmnopqrstuvwxyz"
>    method3
>  end
> end
>
> Does writing it with a case statement like so benefit me?
> lines = File.open("file.csv")
> FasterCSV.parse(lines) do |row|
>  case
>  when ( lines =~ /^blah/)
>    puts "blahblahblah"
>    some_method
>
>  when ( lines =~ /^name/ && row[1] =="123")
>    puts "ping pong abc"
>    another_method
>
>  when ( lines =~ /^address/ && row[1] =="XYZ")
>    puts "abcdefghijklmnopqrstuvwxyz"
>    method3
>  end
> end
>
> While writing this I couldn't figure out how to write my case to be "if
> lines begins with"
>  case "lines =~"
>  when /^blah/
>    puts "blahblahblah"
>    some_method
>
> Lastly is there a "better" way to write an if statement that is
> conditional on a bunch of things like
>  if row[0] == john && row[7] == abc123  && row[8] != nil &&
> somehashtable.has_key?(row2)
>
> Thanks
> --
> Posted via http://www.ruby-forum.com/.
>
>

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