# Sort problem **URL:** \ **Category:** ruby-talk\ **Created:** [6 August 2002 23:54 UTC](https://rubytalk.org/t/sort-problem/1047 "2002-08-06T23:54:47Z")\ **Posts on this page:** 11\ **Page:** 1
**Author:** ![Ian\_Macdonald](https://avatars.discourse-cdn.com/v4/letter/i/f19dbf/32.png) [@Ian\_Macdonald](https://rubytalk.org/u/Ian_Macdonald)\ **Post date:** [6 August 2002 23:54 UTC](https://rubytalk.org/t/sort-problem/1047/1 "2002-08-06T23:54:47Z")
Hi, I have a file with data like this: ina1 ina15 inb12 ina9 inc10 inda12 inef14 inab14 inzz8 inzz80 inzz9 etc. I want to sort it alphabetically on the first part of the string, then numerically on the second part. The sorted file should look like this: ina1 ina9 ina15 inab14 inb12 inc10 inda12 inef14 inzz8 inzz9 inzz80 However, I can’t seem to write the Ruby code to do this properly. Having written the Perl to do this kind of thing many times before, I set about writing it in Perl and sure enough, the Perl version works. The Ruby code is so analagous that I just can’t see where I’m going wrong. Here are the two versions: Perl > **···** > > * * * > > undef $/; > @foo = sort { ($c,$d) = ($a =~ /^([a-z]+)([0-9]+)$/); > ($e,$f) = ($b =~ /^([a-z]+)([0-9]+)$/); > $c cmp $e or $d \<=\> $f} split(/\n/, \<\>); > print join “\n”, @foo’ > > ## Ruby > > $/ = nil > foo = gets.split("\n") > r = /^([a-z]+)([0-9]+)$/ > foo = foo.sort {|a,b| c,d = r.match(a)[1,2] > e,f = r.match(b)[1,2] > c \<=\> e or d.to\_i \<=\> f.to\_i} > puts foo > > The Ruby version outputs this: > > ina1 > ina15 > ina9 > inab14 > inb12 > inc10 > inda12 > inef14 > inzz80 > inzz8 > inzz9 > > which shows that the numeric comparison on the second part of the > string is clearly not working, leading me to suspect that the \<=\> > operator doesn’t work with objects of type Fixnum, but according to > the docs, it gets mixed in from Comparable. > > So, what’s wrong with the Ruby code? This is Ruby 1.6.7, in case that > matters. > > ## Ian > > Ian Macdonald | Somewhere in Tenafly, New Jersey, a > [ian@caliban.org](mailto:ian@caliban.org) | chiropractor is viewing “Leave it to > \> Beaver”! > \> > \> ---
**Author:** ![David\_Alan\_Black1](https://avatars.discourse-cdn.com/v4/letter/d/278dde/32.png) [@David\_Alan\_Black1](https://rubytalk.org/u/David_Alan_Black1)\ **Post date:** [7 August 2002 00:22 UTC](https://rubytalk.org/t/sort-problem/1047/2 "2002-08-07T00:22:24Z")
Hello – > **···** > > On Wed, 7 Aug 2002, Ian Macdonald wrote: > > > Hi, > > > > I have a file with data like this: > > > > ina1 > > ina15 > > inb12 > > ina9 > > inc10 > > inda12 > > inef14 > > inab14 > > inzz8 > > inzz80 > > inzz9 > > > > etc. > > > > I want to sort it alphabetically on the first part of the string, then > > numerically on the second part. > > $/ = nil > > foo = gets.split(“\n”) > > r = /^([a-z]+)([0-9]+)$/ > > foo = foo.sort {|a,b| c,d = r.match(a)[1,2] > > e,f = r.match(b)[1,2] > > c \<=\> e or d.to\_i \<=\> f.to\_i} > > puts foo > > > > [doesn’t work] > > It’s because \<=\> returns -1, 0, or 1, all of which are true in > Ruby. > > You could drop in this last line of the sort: > > (c == e) and (d.to\_i \<=\> f.to\_i) or (c \<=\> e)} > > David > > – > David Alan Black > home: [dblack@candle.superlink.net](mailto:dblack@candle.superlink.net) > work: blackdav@shu.edu > Web: [http://pirate.shu.edu/~blackdav](http://pirate.shu.edu/~blackdav) ---
**Author:** ![Park\_Heesob5](https://avatars.discourse-cdn.com/v4/letter/p/77aa72/32.png) [@Park\_Heesob5](https://rubytalk.org/u/Park_Heesob5)\ **Post date:** [7 August 2002 00:22 UTC](https://rubytalk.org/t/sort-problem/1047/3 "2002-08-07T00:22:54Z")
Hi, “Ian Macdonald” [ian@caliban.org](mailto:ian@caliban.org) wrote in message [news:20020806235442.GA17078@caliban.org](mailto:news:20020806235442.GA17078@caliban.org)… > Hi, > > I have a file with data like this: > > ina1 > ina15 > inb12 > ina9 > inc10 > inda12 > inef14 > inab14 > inzz8 > inzz80 > inzz9 > > etc. > > I want to sort it alphabetically on the first part of the string, then > numerically on the second part. … > ## Ruby > > $/ = nil > foo = gets.split(“\n”) > r = /^([a-z]+)([0-9]+)$/ > foo = foo.sort {|a,b| c,d = r.match(a)[1,2] > e,f = r.match(b)[1,2] > c \<=\> e or d.to\_i \<=\> f.to\_i} > puts foo > > So, what’s wrong with the Ruby code? This is Ruby 1.6.7, in case that > matters. Try this: $/ = nil foo = gets.split(“\n”) r = /^([a-z]+)([0-9]+)$/ foo = foo.sort {|a,b| c,d = r.match(a)[1,2] e,f = r.match(b)[1,2] (c \<=\> e).nonzero? || d.to\_i \<=\> f.to\_i} puts foo > ## Ian > > Ian Macdonald | Somewhere in Tenafly, New Jersey, a > [ian@caliban.org](mailto:ian@caliban.org) | chiropractor is viewing “Leave it to > \> Beaver”! > \> > \> Park Heesob ---
**Author:** ![WATANABE\_Hirofumi1](https://avatars.discourse-cdn.com/v4/letter/w/c2a13f/32.png) [@WATANABE\_Hirofumi1](https://rubytalk.org/u/WATANABE_Hirofumi1)\ **Post date:** [7 August 2002 05:31 UTC](https://rubytalk.org/t/sort-problem/1047/4 "2002-08-07T05:31:47Z")
Hi, Ian Macdonald [ian@caliban.org](mailto:ian@caliban.org) writes: :Ruby :---- : :$/ = nil :foo = gets.split("\n") :r = /^([a-z]+)([0-9]+)$/ :foo = foo.sort {|a,b| c,d = r.match(a)[1,2] : e,f = r.match(b)[1,2] : c \<=\> e or d.to\_i \<=\> f.to\_i} :puts foo How about Array#\<=\> ? [c, d.to\_i] \<=\> [e, f.to\_i] > **···** > > – > eban ---
**Author:** ![David\_Alan\_Black1](https://avatars.discourse-cdn.com/v4/letter/d/278dde/32.png) [@David\_Alan\_Black1](https://rubytalk.org/u/David_Alan_Black1)\ **Post date:** [7 August 2002 00:45 UTC](https://rubytalk.org/t/sort-problem/1047/5 "2002-08-07T00:45:25Z")
Hi – > **···** > > On Wed, 7 Aug 2002, Park Heesob wrote: > > > $/ = nil > > foo = gets.split(“\n”) > > r = /^([a-z]+)([0-9]+)$/ > > foo = foo.sort {|a,b| c,d = r.match(a)[1,2] > > e,f = r.match(b)[1,2] > > (c \<=\> e).nonzero? || d.to\_i \<=\> f.to\_i} > > puts foo > > It’s odd (to me) that #nonzero? doesn’t return true or false, a fact I > wasn’t aware of until looking at this (and wondering why it worked 🙂 > > David > > – > David Alan Black > home: [dblack@candle.superlink.net](mailto:dblack@candle.superlink.net) > work: blackdav@shu.edu > Web: [http://pirate.shu.edu/~blackdav](http://pirate.shu.edu/~blackdav) ---
**Author:** ![Ian\_Macdonald](https://avatars.discourse-cdn.com/v4/letter/i/f19dbf/32.png) [@Ian\_Macdonald](https://rubytalk.org/u/Ian_Macdonald)\ **Post date:** [7 August 2002 01:00 UTC](https://rubytalk.org/t/sort-problem/1047/6 "2002-08-07T01:00:24Z")
> > $/ = nil > > foo = gets.split(“\n”) > > r = /^([a-z]+)([0-9]+)$/ > > foo = foo.sort {|a,b| c,d = r.match(a)[1,2] > > e,f = r.match(b)[1,2] > > c \<=\> e or d.to\_i \<=\> f.to\_i} > > puts foo > > > > [doesn’t work] > > It’s because \<=\> returns -1, 0, or 1, all of which are true in > Ruby. And, of course, I know about those values not returning truth in Ruby, but it continues to bite me when I’m least expecting it. This is one of those few areas where I think the Perl way actually makes more sense. > You could drop in this last line of the sort: > > (c == e) and (d.to\_i \<=\> f.to\_i) or (c \<=\> e)} Thanks. Ian > **···** > > ## On Wed 07 Aug 2002 at 09:22:24 +0900, David Alan Black wrote: > > Ian Macdonald | No house should ever be on any hill or on > [ian@caliban.org](mailto:ian@caliban.org) | anything. It should be of the hill, > \> belonging to it. – Frank Lloyd Wright > \> > \> ---
**Author:** ![Ian\_Macdonald](https://avatars.discourse-cdn.com/v4/letter/i/f19dbf/32.png) [@Ian\_Macdonald](https://rubytalk.org/u/Ian_Macdonald)\ **Post date:** [7 August 2002 06:54 UTC](https://rubytalk.org/t/sort-problem/1047/7 "2002-08-07T06:54:29Z")
Ah, very elegant indeed! Thanks for this idiom. Ian > **···** > > On Wed 07 Aug 2002 at 14:31:47 +0900, WATANABE Hirofumi wrote: > > > Ian Macdonald [ian@caliban.org](mailto:ian@caliban.org) writes: > > > > :Ruby > > :---- > > : > > :$/ = nil > > :foo = gets.split(“\n”) > > :r = /^([a-z]+)([0-9]+)$/ > > :foo = foo.sort {|a,b| c,d = r.match(a)[1,2] > > : e,f = r.match(b)[1,2] > > : c \<=\> e or d.to\_i \<=\> f.to\_i} > > :puts foo > > > > How about Array#\<=\> ? > > > > [c, d.to\_i] \<=\> [e, f.to\_i] > > – > Ian Macdonald | Collaboration, n.: A literary partnership > [ian@caliban.org](mailto:ian@caliban.org) | based on the false assumption that the > \> other fellow can spell. > \> > \> ---
**Author:** ![GOTO\_Kentaro1](https://avatars.discourse-cdn.com/v4/letter/g/e5b9ba/32.png) [@GOTO\_Kentaro1](https://rubytalk.org/u/GOTO_Kentaro1)\ **Post date:** [7 August 2002 16:26 UTC](https://rubytalk.org/t/sort-problem/1047/8 "2002-08-07T16:26:29Z")
And Ruby 1.7 has Array#sort\_by. foo = foo.sort\_by { |i| e,f = r.match(a)[1,2] [e, f.to\_i] } By the way, this example reminds me. I would sometimes like to modifiy an array in a method chain. So, I wrote Array#sub\_at and Array#sub. With this method, above can be rewritten as follows: foo = foo.sort\_by { |i| r.match(a)[1,2].sub\_at(1) { |f| f.to\_i } } Or the original problem [ruby-talk:46468] can be answered as: % cat ruby-talk:46468.rb require “arraysub” puts ARGF.readlines.sort\_by { |line| line.scan(/\D+|\d+/).sub(/\d/) { |f| f.to\_i } } % cat ruby-talk:46468.dat ina1 ina15 inb12 ina9 inc10 inda12 inef14 inab14 inzz8 inzz80 inzz9 % ruby17 ruby-talk:46468.rb ruby-talk:46468.dat ina1 ina9 ina15 inab14 inb12 inc10 inda12 inef14 inzz8 inzz9 inzz80 I’ve put arraysub.rb at [http://www.notwork.org/~gotoken/ruby/p/as-is/arraysub.rb](http://www.notwork.org/~gotoken/ruby/p/as-is/arraysub.rb) – Gotoken > **···** > > At Wed, 7 Aug 2002 14:31:47 +0900, WATANABE Hirofumi wrote: > > > :foo = foo.sort {|a,b| c,d = r.match(a)[1,2] > > : e,f = r.match(b)[1,2] > > : c \<=\> e or d.to\_i \<=\> f.to\_i} > > :puts foo > > > > How about Array#\<=\> ? > > > > [c, d.to\_i] \<=\> [e, f.to\_i] ---
**Author:** ![David\_Alan\_Black1](https://avatars.discourse-cdn.com/v4/letter/d/278dde/32.png) [@David\_Alan\_Black1](https://rubytalk.org/u/David_Alan_Black1)\ **Post date:** [7 August 2002 17:06 UTC](https://rubytalk.org/t/sort-problem/1047/9 "2002-08-07T17:06:03Z")
Hi – > **···** > > On Thu, 8 Aug 2002, GOTO Kentaro wrote: > > > And Ruby 1.7 has Array#sort\_by. > > > > foo = foo.sort\_by { |i| > > e,f = r.match(a)[1,2] > > foo = foo.sort\_by { |i| r.match(a)[1,2].sub\_at(1) { |f| f.to\_i } } > > s/|i|/|a|/g # 🙂 > > David > > – > David Alan Black > home: [dblack@candle.superlink.net](mailto:dblack@candle.superlink.net) > work: blackdav@shu.edu > Web: [http://pirate.shu.edu/~blackdav](http://pirate.shu.edu/~blackdav) ---
**Author:** ![HAL\_9000](https://avatars.discourse-cdn.com/v4/letter/h/90ced4/32.png) [@HAL\_9000](https://rubytalk.org/u/HAL_9000)\ **Post date:** [7 August 2002 17:10 UTC](https://rubytalk.org/t/sort-problem/1047/10 "2002-08-07T17:10:01Z")
puts “Looks like we’re becoming a forum” puts “where we can’t talk at all unless” puts “it’s in code or codelike form.” puts “:)” puts “Cheers,\nHal” # Or perhaps Hal.cheers! > **···** > > ----- Original Message ----- > From: “David Alan Black” [dblack@candle.superlink.net](mailto:dblack@candle.superlink.net) > To: “ruby-talk ML” [ruby-talk@ruby-lang.org](mailto:ruby-talk@ruby-lang.org) > Sent: Wednesday, August 07, 2002 12:06 PM > Subject: Re: sort problem > > > s/|i|/|a|/g # 🙂 ---
**Author:** ![GOTO\_Kentaro1](https://avatars.discourse-cdn.com/v4/letter/g/e5b9ba/32.png) [@GOTO\_Kentaro1](https://rubytalk.org/u/GOTO_Kentaro1)\ **Post date:** [7 August 2002 21:27 UTC](https://rubytalk.org/t/sort-problem/1047/11 "2002-08-07T21:27:31Z")
=begin > From: “David Alan Black” [dblack@candle.superlink.net](mailto:dblack@candle.superlink.net) > To: “ruby-talk ML” [ruby-talk@ruby-lang.org](mailto:ruby-talk@ruby-lang.org) > > s/|i|/|a|/g # 🙂 > puts “Looks like we’re becoming a forum” > puts “where we can’t talk at all unless” > puts “it’s in code or codelike form.” > puts “:)” > > puts “Cheers,\nHal” # Or perhaps Hal.cheers! > =end %( Oops! Thank you David for correcting. And for cheerful comment, Hal 😃 – Gotoken ;). display > **···** > > At Thu, 8 Aug 2002 02:10:01 +0900, Hal E. Fulton [hal9000@hypermetrics.com](mailto:hal9000@hypermetrics.com) wrote: