# Formatting to "Thousands" **URL:** \ **Category:** ruby-talk\ **Created:** [28 February 2006 11:08 UTC](https://rubytalk.org/t/formatting-to-thousands/25285 "2006-02-28T11:08:36Z")\ **Posts on this page:** 9\ **Page:** 1
**Author:** ![Barrie\_Jarman](https://avatars.discourse-cdn.com/v4/letter/b/6de8d8/32.png) [@Barrie\_Jarman](https://rubytalk.org/u/Barrie_Jarman)\ **Post date:** [28 February 2006 11:08 UTC](https://rubytalk.org/t/formatting-to-thousands/25285/1 "2006-02-28T11:08:36Z")
A colleague of mine wishes to format a float to include commas at thousand values, for example 12345.21 becomes 12,345.21 Is there any inbuilt functionality to format this, or are we better of writing something ourselves... > **···** > > -- > Posted via [NewsDemon.com](http://NewsDemon.com) - Premium Uncensored Newsgroup Service >       -------\>\>\>\>\>\>[http://www.NewsDemon.com](http://www.NewsDemon.com)\<\<\<\<\<\<------ > Unlimited Access, Anonymous Accounts, Uncensored Broadband Access ---
**Author:** ![James\_Edward\_Gray\_II](https://avatars.discourse-cdn.com/v4/letter/j/ea5d25/32.png) [@James\_Edward\_Gray\_II](https://rubytalk.org/u/James_Edward_Gray_II)\ **Post date:** [28 February 2006 13:53 UTC](https://rubytalk.org/t/formatting-to-thousands/25285/2 "2006-02-28T13:53:34Z")
It's not built-in, but it's also pretty easy to roll one: def commify( number )    number.to\_s.reverse.gsub!(/(\d\d\d)(?=\d)(?!\d\*\.)/, '\1,').reverse end Hope that helps. James Edward Gray II > **···** > > On Feb 28, 2006, at 5:08 AM, Barrie Jarman wrote: > > > A colleague of mine wishes to format a float to include commas at thousand > > values, for example > > 12345.21 becomes > > 12,345.21 > > > > Is there any inbuilt functionality to format this, or are we better of > > writing something ourselves... ---
**Author:** ![Shane\_Emmons](https://avatars.discourse-cdn.com/v4/letter/s/65b543/32.png) [@Shane\_Emmons](https://rubytalk.org/u/Shane_Emmons)\ **Post date:** [28 February 2006 16:13 UTC](https://rubytalk.org/t/formatting-to-thousands/25285/3 "2006-02-28T16:13:38Z")
I have to say, that is some great Regex Fu. I was looking to do something similar but your solution is much nicer! ---
**Author:** ![Barrie\_Jarman](https://avatars.discourse-cdn.com/v4/letter/b/6de8d8/32.png) [@Barrie\_Jarman](https://rubytalk.org/u/Barrie_Jarman)\ **Post date:** [28 February 2006 16:48 UTC](https://rubytalk.org/t/formatting-to-thousands/25285/4 "2006-02-28T16:48:38Z")
Implemented this into the float class. Adds check to make sure 0 is handled properly and adds for two decimal places (sorry, probably wasn't specific enough before). def to\_finance   if self != 0    number = sprintf("%.2f", self)     number.to\_s.reverse.gsub!(/(\d\d\d)(?=\d)(?!\d\*\.)/, '\1,').reverse    else     sprintf("%.2f", self)    end end "James Edward Gray II" \ wrote in message news:47AC1DDA-5D15-461F-AEB2-40B5E23903B1@grayproductions.net... > **···** > > > On Feb 28, 2006, at 5:08 AM, Barrie Jarman wrote: > > > > > A colleague of mine wishes to format a float to include commas at > > > thousand > > > values, for example > > > 12345.21 becomes > > > 12,345.21 > > > > > > Is there any inbuilt functionality to format this, or are we better of > > > writing something ourselves... > > > > It's not built-in, but it's also pretty easy to roll one: > > > > def commify( number ) > >   number.to\_s.reverse.gsub!(/(\d\d\d)(?=\d)(?!\d\*\.)/, '\1,').reverse > > end > > > > Hope that helps. > > > > James Edward Gray II > > -- > Posted via NewsDemon.com - Premium Uncensored Newsgroup Service >       -------\>\>\>\>\>\>[http://www.NewsDemon.com](http://www.NewsDemon.com)\<\<\<\<\<\<------ > Unlimited Access, Anonymous Accounts, Uncensored Broadband Access ---
**Author:** ![Jeff\_Schwab](https://avatars.discourse-cdn.com/v4/letter/j/b5ac83/32.png) [@Jeff\_Schwab](https://rubytalk.org/u/Jeff_Schwab)\ **Post date:** [28 February 2006 16:53 UTC](https://rubytalk.org/t/formatting-to-thousands/25285/5 "2006-02-28T16:53:36Z")
James Edward Gray II wrote: > def commify( number ) >   number.to\_s.reverse.gsub!(/(\d\d\d)(?=\d)(?!\d\*\.)/, '\1,').reverse > end That's nice, except that gsub! returns nil if no substitutions are performed, e.g. if the number has fewer than 4 digits. This can result in an exception like:    main.rb:3:in `commify':      undefined method `reverse' for nil:NilClass(NoMethodError) Of course, you could just break the chain across multiple lines:    def commify(number)      s = number.to\_s      s.reverse!      s.gsub!(/(\d\d\d)(?=\d)(?!\d\*\.)/, '\1,')      s.reverse!    end ---
**Author:** ![James\_Edward\_Gray\_II](https://avatars.discourse-cdn.com/v4/letter/j/ea5d25/32.png) [@James\_Edward\_Gray\_II](https://rubytalk.org/u/James_Edward_Gray_II)\ **Post date:** [28 February 2006 16:59 UTC](https://rubytalk.org/t/formatting-to-thousands/25285/6 "2006-02-28T16:59:37Z")
Good catch. I originally had it in multiple lines and I forgot to remove the ! when I shortened it for this post. Thanks. James Edward Gray II > **···** > > On Feb 28, 2006, at 10:53 AM, Jeffrey Schwab wrote: > > > James Edward Gray II wrote: > > > > > def commify( number ) > > >   number.to\_s.reverse.gsub!(/(\d\d\d)(?=\d)(?!\d\*\.)/, '\1,').reverse > > > end > > > > That's nice, except that gsub! returns nil if no substitutions are performed, e.g. if the number has fewer than 4 digits. This can result in an exception like: > > > >   main.rb:3:in `commify': > >     undefined method `reverse' for nil:NilClass(NoMethodError) > > > > Of course, you could just break the chain across multiple lines: > > > >   def commify(number) > >     s = number.to\_s > >     s.reverse! > >     s.gsub!(/(\d\d\d)(?=\d)(?!\d\*\.)/, '\1,') > >     s.reverse! > >   end ---
**Author:** ![Kevin\_Olbrich](https://avatars.discourse-cdn.com/v4/letter/k/59ef9b/32.png) [@Kevin\_Olbrich](https://rubytalk.org/u/Kevin_Olbrich)\ **Post date:** [28 February 2006 17:02 UTC](https://rubytalk.org/t/formatting-to-thousands/25285/7 "2006-02-28T17:02:48Z")
Or you could just use 'gsub' instead of 'gsub!' and avoid the nil \_Kevin > **···** > > -----Original Message----- > From: Jeffrey Schwab [mailto:jeff@schwabcenter.com] > Sent: Tuesday, February 28, 2006 11:54 AM > To: ruby-talk ML > Subject: Re: Formatting to "Thousands" > > James Edward Gray II wrote: > > > def commify( number ) > >   number.to\_s.reverse.gsub!(/(\d\d\d)(?=\d)(?!\d\*\.)/, '\1,').reverse > > end > > That's nice, except that gsub! returns nil if no substitutions are > performed, e.g. if the number has fewer than 4 digits. This can result in > an exception like: > >    main.rb:3:in `commify': >      undefined method `reverse' for nil:NilClass(NoMethodError) > > Of course, you could just break the chain across multiple lines: > >    def commify(number) >      s = number.to\_s >      s.reverse! >      s.gsub!(/(\d\d\d)(?=\d)(?!\d\*\.)/, '\1,') >      s.reverse! >    end ---
**Author:** ![Logan\_Capaldo](https://avatars.discourse-cdn.com/v4/letter/l/7ea924/32.png) [@Logan\_Capaldo](https://rubytalk.org/u/Logan_Capaldo)\ **Post date:** [1 March 2006 03:56 UTC](https://rubytalk.org/t/formatting-to-thousands/25285/8 "2006-03-01T03:56:55Z")
I don't know why but using regexps to do this kind of scares me. Maybe its cause I don't have as much regexp fu but it just seems like ruby perl ruby Not that I have anything against perl or regexps, but that particular regexp seems to scream "I'm doing this with a regexp not because it's easier but because it's faster and shorter." Not that that's wrong. Hmm I seem to be trying really hard not to offend anyone :-p. I guess a rule of thumb for me is more than 1 lookahead assertion and my eyes glaze over 😉 > **···** > > On Feb 28, 2006, at 11:59 AM, James Edward Gray II wrote: > > > On Feb 28, 2006, at 10:53 AM, Jeffrey Schwab wrote: > > > > > James Edward Gray II wrote: > > > > > > > def commify( number ) > > > >   number.to\_s.reverse.gsub!(/(\d\d\d)(?=\d)(?!\d\*\.)/, '\1,').reverse > > > > end > > > > > > That's nice, except that gsub! returns nil if no substitutions are performed, e.g. if the number has fewer than 4 digits. This can result in an exception like: > > > > > >   main.rb:3:in `commify': > > >     undefined method `reverse' for nil:NilClass(NoMethodError) > > > > > > Of course, you could just break the chain across multiple lines: > > > > > >   def commify(number) > > >     s = number.to\_s > > >     s.reverse! > > >     s.gsub!(/(\d\d\d)(?=\d)(?!\d\*\.)/, '\1,') > > >     s.reverse! > > >   end > > > > Good catch. I originally had it in multiple lines and I forgot to remove the ! when I shortened it for this post. > > > > Thanks. > > > > James Edward Gray II ---
**Author:** ![Jeff\_Schwab](https://avatars.discourse-cdn.com/v4/letter/j/b5ac83/32.png) [@Jeff\_Schwab](https://rubytalk.org/u/Jeff_Schwab)\ **Post date:** [1 March 2006 16:23 UTC](https://rubytalk.org/t/formatting-to-thousands/25285/9 "2006-03-01T16:23:37Z")
Logan Capaldo wrote: > > > James Edward Gray II wrote: > > > > > > > def commify( number ) > > > >   number.to\_s.reverse.gsub!(/(\d\d\d)(?=\d)(?!\d\*\.)/, '\1,').reverse > > > > end > > > > > > That's nice, except that gsub! returns nil if no substitutions are performed, e.g. if the number has fewer than 4 digits. This can result in an exception like: > > > > > >   main.rb:3:in `commify': > > >     undefined method `reverse' for nil:NilClass(NoMethodError) > > > > > > Of course, you could just break the chain across multiple lines: > > > > > >   def commify(number) > > >     s = number.to\_s > > >     s.reverse! > > >     s.gsub!(/(\d\d\d)(?=\d)(?!\d\*\.)/, '\1,') > > >     s.reverse! > > >   end > > > > Good catch. I originally had it in multiple lines and I forgot to remove the ! when I shortened it for this post. > > > > Thanks. > > > > James Edward Gray II > > I don't know why but using regexps to do this kind of scares me. Maybe its cause I don't have as much regexp fu but it just seems like > ruby > perl > ruby > > Not that I have anything against perl or regexps, but that particular regexp seems to scream "I'm doing this with a regexp not because it's easier but because it's faster and shorter." Not that that's wrong. Hmm I seem to be trying really hard not to offend anyone :-p. I guess a rule of thumb for me is more than 1 lookahead assertion and my eyes glaze over 😉 Try the Friedl book. It will open your eyes. 🙂 > **···** > > > On Feb 28, 2006, at 11:59 AM, James Edward Gray II wrote: > > > > > On Feb 28, 2006, at 10:53 AM, Jeffrey Schwab wrote: