Regualr expression question

ruby-talk
1

The "Ruby_RegularExpression" sample application in the
javapassion rubyonrails tutorial has this code

puts "----Regular Expression"
puts a = "hello there"
puts a[1] #=> 101
puts a[1,3] #=> "ell"

How do you get 101 from a[1]

2

The "Ruby_RegularExpression" sample application in the
javapassion rubyonrails tutorial has this code

puts "----Regular Expression"
puts a = "hello there"
puts a[1] #=> 101
puts a[1,3] #=> "ell"

How do you get 101 from a[1]

It's the value associated with the character e in ASCII.

In irb:

> RUBY_VERSION
=> "1.8.6"
>> a = 'hello'
=> "hello"
>> a[1]
=> 101
>> ?e
=> 101
>> a[1 ,1]
=> "e"
>>

If you look at the ri documnetation for String# in Ruby 1.8.6 you can see:

-------------------------------------------------------------- String#
      str[fixnum] => fixnum or nil
      str[fixnum, fixnum] => new_str or nil
      str[range] => new_str or nil
      str[regexp] => new_str or nil
      str[regexp, fixnum] => new_str or nil
      str[other_str] => new_str or nil
[...]

···

On Apr 16, 2009, at 6:40 PM, Reg wrote:
------------------------------------------------------------------------
      Element Reference---If passed a single +Fixnum+, returns the code
      of the character at that position.
[...]

In Ruby 1.9 things change so that you always get a String or nil back from String#:

irb(main):001:0> RUBY_VERSION
=> "1.9.2"
irb(main):002:0> a = 'hello'
=> "hello"
irb(main):003:0> a[1]
=> "e"
irb(main):004:0>

Hope this helps,

Mike

--

Mike Stok <mike@stok.ca>
http://www.stok.ca/~mike/

The "`Stok' disclaimers" apply.

3

Its a great help!
Thanks Mike

···

On Thu, 16 Apr 2009 18:02:52 -0500, Mike Stok <mike@stok.ca> wrote:

How do you get 101 from a[1]

It's the value associated with the character e in ASCII.

In irb:

> RUBY_VERSION
=> "1.8.6"
>> a = 'hello'
=> "hello"
>> a[1]
=> 101
>> ?e
=> 101
>> a[1 ,1]
=> "e"
>>

If you look at the ri documnetation for String# in Ruby 1.8.6 you
can see:

-------------------------------------------------------------- String#
     str[fixnum] => fixnum or nil
     str[fixnum, fixnum] => new_str or nil
     str[range] => new_str or nil
     str[regexp] => new_str or nil
     str[regexp, fixnum] => new_str or nil
     str[other_str] => new_str or nil
[...]
------------------------------------------------------------------------
     Element Reference---If passed a single +Fixnum+, returns the code
     of the character at that position.
[...]

In Ruby 1.9 things change so that you always get a String or nil back
from String#:

irb(main):001:0> RUBY_VERSION
=> "1.9.2"
irb(main):002:0> a = 'hello'
=> "hello"
irb(main):003:0> a[1]
=> "e"
irb(main):004:0>

Hope this helps,

Mike