Thanks to anyone who replied. You gave me pretty good explanations Now I better understand why I'll always be an amateur (and be delighted to). Le 8 avr. 2010 à 18:17, Frederick Cheung a écrit :
> > > On Apr 8, 4:08 pm, Christophe Decaux <[email protected]> > wrote: >> Hi there, >> >> I've been investigating the railscasts episodes which talk about complex >> forms and I ran across this notation in the example code provided in part 3 >> of the episode. >> >> at some point in a model method, there is this line: >> >> tasks.reject(&:new_record?).each do |task| >> >> I have no problem with the ".each do..." stuff, I guess that "reject" is >> quite the opposite of find but I quite don't understand the "&:new_record?" >> notation >> What is the purpose of the & >> Is it some sort of Ruby idiom > > That is equivalent to tasks.reject {|t| t.new_record?} - It's > shorthand for when you want to just call one method on every object > yielded by the block (performance wise there are slight differences to > the long hand version on some versions of ruby (before this was made > part of core)). More generally passing an argument prefixed by & to a > method tells the method "you should use this argument as your block", > so for example if you had a proc object you can use that syntax to say > to a method 'when you call yield, call this proc'. Ruby calls to_proc > on such arguments and rails adds a to_proc method on Symbol which > creates an appropriate proc for you > > Fred > > >> >> I have the feeling that it should read "find any task object that is not >> new" (i.e. created but not saved) >> >> How would you customize it to achieve this goal : >> >> Find the last task object (sorted by id's) that is not new >> >> Thanks a lot in advance >> Christophe > > -- > You received this message because you are subscribed to the Google Groups > "Ruby on Rails: Talk" group. > To post to this group, send email to [email protected]. > To unsubscribe from this group, send email to > [email protected]. > For more options, visit this group at > http://groups.google.com/group/rubyonrails-talk?hl=en. > -- You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en.
