From: Sam Duncan <sduncan@...>
Date: 2013-04-18T05:37:14+09:00
Subject: Re: String index produces unanticipated result

On 04/18/2013 08:24 AM, Thomas Luedeke wrote:
> I have the following string I am pulling from a file (asterisks used to
> show boundaries of line, and are not actually there:
>
> *    9    3    3    0    0*
>
> I want to test to see if a "9" is in the first five columns of the line.
> Typically it is in column five, but not necessarily.
>
> I tried the "puts line.strip[0]" command, which returns "57".  Huh?
> Where did "57" come from??  Same thing happens with strip!.
>
> Why isn't this simply removing the leading white space and returning
> "9"??  I don't understand how to accomplish my task now.
>
> I tried the online irb, and it gave me "9", like I'd have expected.
>
The 57 you are getting is the ordinal of the string "9";

irb(main):001:0> "9".ord
=> 57

In Ruby 1.8 I believe an index into a string gave you this value, rather 
than the character at that index. In Ruby 1.9 it was changed to give you 
what you are expecting here;

irb(main):002:0> "9"[0]
=> "9"

Something like this would probably work for you in both flavours of Ruby;

irb(main):003:0> foo.split[0,5].include? "9"
=> true

Split the string, take a slice of the first five values (columns), and 
check for membership.

Sam