# Succ distance between two strings **URL:** \ **Category:** ruby-talk\ **Created:** [6 November 2004 13:34 UTC](https://rubytalk.org/t/succ-distance-between-two-strings/14648 "2004-11-06T13:34:07Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![T\_Onoma](https://avatars.discourse-cdn.com/v4/letter/t/c2a13f/32.png) [@T\_Onoma](https://rubytalk.org/u/T_Onoma)\ **Post date:** [6 November 2004 13:34 UTC](https://rubytalk.org/t/succ-distance-between-two-strings/14648/1 "2004-11-06T13:34:07Z")
Is there an efficient way to calculate the "succ distance" between two strings (without iterating over each succession)? Examples:   'a'..'a' 0   'a'..'b' 1   'a'..'z' 25   'a'..'aa' 26 T. ---
**Author:** ![David\_A\_Black3](https://avatars.discourse-cdn.com/v4/letter/d/6a8cbe/32.png) [@David\_A\_Black3](https://rubytalk.org/u/David_A_Black3)\ **Post date:** [6 November 2004 14:07 UTC](https://rubytalk.org/t/succ-distance-between-two-strings/14648/2 "2004-11-06T14:07:59Z")
Hi -- > **···** > > On Sat, 6 Nov 2004, trans. (T. Onoma) wrote: > > > Is there an efficient way to calculate the "succ distance" between two strings > > (without iterating over each succession)? Examples: > > > >   'a'..'a' 0 > >   'a'..'b' 1 > >   'a'..'z' 25 > >   'a'..'aa' 26 > > 'a'...'aa'.to\_a.size # would be one way > > David > > -- > David A. Black > dblack@wobblini.net ---
**Author:** ![gabriele\_renzi](https://avatars.discourse-cdn.com/v4/letter/g/e19b73/32.png) [@gabriele\_renzi](https://rubytalk.org/u/gabriele_renzi)\ **Post date:** [6 November 2004 14:38 UTC](https://rubytalk.org/t/succ-distance-between-two-strings/14648/3 "2004-11-06T14:38:40Z")
trans. (T. Onoma) ha scritto: > Is there an efficient way to calculate the "succ distance" between two strings (without iterating over each succession)? Examples: > >   'a'..'a' 0 >   'a'..'b' 1 >   'a'..'z' 25 >   'a'..'aa' 26 > > T. my tentativ impl would be class String   def value      i=-26      split(//).inject(0){|x,y|        i+=26        x+y[0]-?a+i      }   end end class Range   def dist    max.value - min.value   end end p 'aa'.value - 'a'.value p 'a'.value - 'a'.value p ('a'..'b').dist p ('a'..'z').dist note that '-?a' could be moved in the 'i' initialization but I'm running away 🙂 ---
**Author:** ![Simon\_Conrad-Armes](https://avatars.discourse-cdn.com/v4/letter/s/3da27b/32.png) [@Simon\_Conrad-Armes](https://rubytalk.org/u/Simon_Conrad-Armes)\ **Post date:** [6 November 2004 14:23 UTC](https://rubytalk.org/t/succ-distance-between-two-strings/14648/4 "2004-11-06T14:23:11Z")
That still iterates over all elements but it looks sweet 🙂 Only for large strings would be a problem My stab: def diff\_succ s1, s2    t1 = t2 = 0    s1.each\_byte{|c| t1 = t1\*26 + c - 96}    s2.each\_byte{|c| t2 = t2\*26 + c - 96}    t2 - t1 end def t s1, s2    puts "#{s1}..#{s2} =\> #{diff\_succ s1, s2}" end t 'a', 'a' #0 t 'a', 'b' #1 t 'a', 'z' #25 t 'a', 'aa' #26 t 'A', 'B' t 'A', 'Z' t 'A', 'AA' output: a..a =\> 0 a..b =\> 1 a..z =\> 25 a..aa =\> 26 A..B =\> 1 A..Z =\> 25 A..AA =\> -806 Notice how it breaks on multi-letter uppercase strings? that is because of the -96. Maybe one should just lowercase the args... /Curne > **···** > > On Nov 6, 2004, at 3:07 PM, David A. Black wrote: > > > Hi -- > > > > On Sat, 6 Nov 2004, trans. (T. Onoma) wrote: > > > > > Is there an efficient way to calculate the "succ distance" between two strings > > > (without iterating over each succession)? Examples: > > > > > >   'a'..'a' 0 > > >   'a'..'b' 1 > > >   'a'..'z' 25 > > >   'a'..'aa' 26 > > > > 'a'...'aa'.to\_a.size # would be one way > > -- > Mailing lists confuse me. Often I don't recognize my own posts and set about writing a flaming reply where I violently disagree. [curne@curnomatic.dk] ---
**Author:** ![Chad\_Fowler4](https://avatars.discourse-cdn.com/v4/letter/c/9fc29f/32.png) [@Chad\_Fowler4](https://rubytalk.org/u/Chad_Fowler4)\ **Post date:** [6 November 2004 14:25 UTC](https://rubytalk.org/t/succ-distance-between-two-strings/14648/5 "2004-11-06T14:25:14Z")
For the first 3 examples you can also treat them as characters and do: ?a - ?a #=\> 0 ?b - ?a #=\> 1 ?z - ?a #=\> 25 Not exactly what you want though. Chad Fowler [http://chadfowler.com](http://chadfowler.com) > **[Ruby Central](https://rubycentral.org)** > > Supporting the Ruby Community Since 2001 > **[WebMD - Better information. Better health.](https://www.rubygarden.org/)** > > The leading source for trustworthy and timely health and medical news and information. Providing credible health information, supportive community, and educational services by blending award-winning expertise in content, community services, expert... [http://rubygems.rubyforge.org](http://rubygems.rubyforge.org) (over 20,000 gems served!) > **···** > > On Sat, 6 Nov 2004 23:07:59 +0900, David A. Black \ wrote: > > > Hi -- > > > > On Sat, 6 Nov 2004, trans. (T. Onoma) wrote: > > > > \> > > \> Is there an efficient way to calculate the "succ distance" between two strings > > \> (without iterating over each succession)? Examples: > > \> > > \> 'a'..'a' 0 > > \> 'a'..'b' 1 > > \> 'a'..'z' 25 > > \> 'a'..'aa' 26 > > > > 'a'...'aa'.to\_a.size # would be one way ---
**Author:** ![T\_Onoma](https://avatars.discourse-cdn.com/v4/letter/t/c2a13f/32.png) [@T\_Onoma](https://rubytalk.org/u/T_Onoma)\ **Post date:** [6 November 2004 21:27 UTC](https://rubytalk.org/t/succ-distance-between-two-strings/14648/6 "2004-11-06T21:27:45Z")
Thanks all for the responses. Looks like it \_might\_ be doable, but the complexity quickly racks up. The presented quick stabs at it fail on capital letters and other characters. Running away might be the best course of action 😉 T. > **···** > > On Saturday 06 November 2004 09:38 am, gabriele renzi wrote: > > > trans. (T. Onoma) ha scritto: > > \> Is there an efficient way to calculate the "succ distance" between two > > \> strings (without iterating over each succession)? Examples: > > \> > > \> 'a'..'a' 0 > > \> 'a'..'b' 1 > > \> 'a'..'z' 25 > > \> 'a'..'aa' 26 > > \> > > \> T. > > > > my tentativ impl would be > > class String > >   def value > >      i=-26 > >      split(//).inject(0){|x,y| > >        i+=26 > >        x+y[0]-?a+i > >      } > >   end > > end > > > > class Range > >   def dist > >    max.value - min.value > >   end > > end > > p 'aa'.value - 'a'.value > > p 'a'.value - 'a'.value > > p ('a'..'b').dist > > p ('a'..'z').dist > > > > note that '-?a' could be moved in the 'i' initialization but I'm running > > away 🙂 > > -- > ( o \_ カラチ > // trans. > / \ transami@runbox.com > > I don't give a damn for a man that can only spell a word one way. > -Mark Twain > > [8,16,20,29,78,65,2,14,26,12,12,28,71,114,12,13,12,82,72,21,17,4,10,2,95]. > each\_with\_index{|x,i| $\>\<\<(x^'Begin landing your troops'[i]).chr} > -Tadayoshi Funaba ---
**Author:** ![Brian\_SchrA\_der](https://avatars.discourse-cdn.com/v4/letter/b/c67d28/32.png) [@Brian\_SchrA\_der](https://rubytalk.org/u/Brian_SchrA_der)\ **Post date:** [8 November 2004 12:50 UTC](https://rubytalk.org/t/succ-distance-between-two-strings/14648/7 "2004-11-08T12:50:42Z")
That does not work, as the ... have a very low binding. It seems a common error I made often. bschroed@black:~ $ irb irb(main):001:0\> 'a'...'aa'.to\_a.size =\> "a"...1 irb(main):002:0\> ('a'...'aa').to\_a.size =\> 26 Regards, Brian > **···** > > On Sat, 6 Nov 2004 23:07:59 +0900 "David A. Black" \ wrote: > > > Hi -- > > > > On Sat, 6 Nov 2004, trans. (T. Onoma) wrote: > > > > \> > > \> Is there an efficient way to calculate the "succ distance" between two strings > > \> (without iterating over each succession)? Examples: > > \> > > \> 'a'..'a' 0 > > \> 'a'..'b' 1 > > \> 'a'..'z' 25 > > \> 'a'..'aa' 26 > > > > 'a'...'aa'.to\_a.size # would be one way > > -- > Brian Schröder > [http://www.brian-schroeder.de/](http://www.brian-schroeder.de/) ---
**Author:** ![David\_A\_Black3](https://avatars.discourse-cdn.com/v4/letter/d/6a8cbe/32.png) [@David\_A\_Black3](https://rubytalk.org/u/David_A_Black3)\ **Post date:** [8 November 2004 13:31 UTC](https://rubytalk.org/t/succ-distance-between-two-strings/14648/8 "2004-11-08T13:31:48Z")
Hi -- > **···** > > On Mon, 8 Nov 2004, Brian [ISO-8859-15] Schröder wrote: > > > On Sat, 6 Nov 2004 23:07:59 +0900 \> "David A. Black" \ wrote: > > > > \> Hi -- > > \> > > \> On Sat, 6 Nov 2004, trans. (T. Onoma) wrote: > > \> > > \> \> > > \> \> Is there an efficient way to calculate the "succ distance" between two strings > > \> \> (without iterating over each succession)? Examples: > > \> \> > > \> \> 'a'..'a' 0 > > \> \> 'a'..'b' 1 > > \> \> 'a'..'z' 25 > > \> \> 'a'..'aa' 26 > > \> > > \> 'a'...'aa'.to\_a.size # would be one way > > > > That does not work, as the ... have a very low binding. It seems a common error I made often. > > > > bschroed@black:~ $ irb > > irb(main):001:0\> 'a'...'aa'.to\_a.size > > =\> "a"...1 > > irb(main):002:0\> ('a'...'aa').to\_a.size > > =\> 26 > > Whoops -- I did actually do it correctly in irb, to make sure, and > then wrote it out wrongly instead of pasting it. > > It's like putting (i.e., putt-ing, in golf) -- you can never take it > for granted 🙂 > > David > > -- > David A. Black > dblack@wobblini.net