From: "Michael W. Ryder" <_mwryder@...>
Date: 2007-04-24T02:40:10+09:00
Subject: Re: Question regarding design of the String Class

Roland Crosby wrote:
> On Apr 22, 2007, at 10:35 PM, Michael W. Ryder wrote:
>> Roland Crosby wrote:
>>> On Apr 22, 2007, at 10:00 PM, Michael W. Ryder wrote:
>>>> Was there a reason the string class was implemented with str[i] 
>>>> returning the code of position i in str?  The reason I ask this is 
>>>> that in other languages str[i] returns the string starting at 
>>>> position i. For example C uses t = strcpy(str[i]) and Business Basic 
>>>> uses S$=T$(I) to copy a string from position i.
>>>> I can see no way to do this in Ruby other than using something like: 
>>>> t = str[i,9999].  It seemed strange that copying ranges of strings 
>>>> uses the same format as C (t =strncpy(str[i],n)) but not when 
>>>> copying the remainder.
>>> Try str[i,-1], or one of the myriad other ways to access ranges of a 
>>> string as defined in String#[]
>> If I enter:
>>     a = "This is a test."
>>     b = a[1, -1]
>>     puts b
>> irb returns nil.  Obviously this is not what I want.  If instead of -1 
>> I use 9999 it returns "his a test." which is what I was looking for.  
>> This seems like a kludge and an inconsistency.  Like I pointed out 
>> other languages just use b = a[1] to get the remainder of the string 
>> instead of 104.  The string class already has methods like each_byte 
>> for converting characters in a string to a number, so why does it need 
>> another shortcut for something that is probably very rarely used.
> 
> Sorry, I meant a[1..-1] rather than a[1,-1]. 

I figured that out right after I posted my reply.  I had forgotten about 
ranges as I have never programmed in a language that used them before. 
The little differences can really get you, especially when you find so 
many similarities.


I don't know why Ruby
> returns the character codes like that, but for what it's worth, I 
> believe Ruby 1.9 is going to switch to returning a single-character 
> string when you put one integer in String#[].
>