From: Dave Thomas <Dave@...>
Date: 2000-10-21T15:25:00+09:00
Subject: [ruby-talk:5728] Re: String#slice surprise

"Guy N. Hurst" <gnhurst@hurstlinks.com> writes:

> Suppose $string="Hello there"
> 
> In Perl (and PHP),
> 
> substr($string, 4, 1) == "o"
> and substr($string, 4, 3) == "o t"
> but substr($string, 4) == "o there"
> 
> In other words, if you leave out the third parameter ('length'), 
> it just goes to the end of the string. Makes perfect sense, and
> is balanced well by the functionality to extract a single character.
> 
> In Ruby,
> 
> string.slice(4,1) == "o"
> and string.slice(4,3) == "o t"
> but string.slice(4) == 111  	# (!)

Ruby gives you the option of returning a single character as either a
string or as a byte. This flexibility comes in vry handy when you're
dealing with strings that contain binary data.

> What is worse, if I *do* wish to get a substring from a starting
> position to the end, it seems I have to use an embedded function:
> 
> string.slice(4..string.size) == "o there"

Negative indices count from the end of a string

  string = "hello there"	
  string[4..-1]		# => "o there"
  string[-4, 2]		# => "he"
  string[-6..-2]        # => " ther"


Regards


Dave