# Arrayfields-3.7.0 **URL:** \ **Category:** Ruby\ **Created:** [April 3, 2007, 8:55pm UTC](https://www.ruby-forum.com/t/arrayfields-3-7-0/91014 "2007-04-03T20:55:56Z")\ **Posts on this page:** 1\ **Page:** 1
**Author:** ![unknown](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/u/4bbf92/32.png) [@unknown](https://www.ruby-forum.com/u/unknown)\ **Post date:** [April 3, 2007, 8:55pm UTC](https://www.ruby-forum.com/t/arrayfields-3-7-0/91014/1 "2007-04-03T20:55:56Z")
NAME arrayfields.rb URIS [http://rubyforge.org/projects/arrayfields/](http://rubyforge.org/projects/arrayfields/) [http://www.codeforpeople.com/lib/ruby/arrayfields/](http://www.codeforpeople.com/lib/ruby/arrayfields/) [http://raa.ruby-lang.org/project/arrayfields/](http://raa.ruby-lang.org/project/arrayfields/) SYNOPSIS require ‘arrayfields’ ``` fields = 'name', 'age' a = ['zaphod', 42] a.fields = fields a['name'] #=> 'zaphod' a[:name] #=> 'zaphod' a.indices 'name', 'age' #=> ['zaphod', 42] ``` DESCRIPTION allow keyword access to array instances. arrayfields works by adding only a few methods to arrays, namely #fields= and fields, but the #fields= method is hooked to extend arrays on a per object basis. in otherwords **only** those arrays whose fields are set will have auto-magical keyword access bestowed on them - all other arrays remain unaffected. arrays with keyword access require much less memory when compared to hashes/objects and yet still provide fast lookup. LIST OF OVERRIDDEN METHODS Array#[] Array#slice Array#[]= Array#at Array#delete\_at Array#fill Array#values\_at Array#indices Array#indexes Array#slice! LIST OF HASH-LIKE METHODS Array#each\_with\_field Array#each\_pair Array#each\_key Array#each\_value Array#fetch Array#has\_key? Array#member? Array#key? Array#has\_value? Array#value? Array#keys Array#store Array#values Array#to\_hash Array#to\_h Array#update Array#replace Array#invert LIST OF ADDED Array METHODS Array#fields= Array#fields LIST OF ADDED Array CLASS METHODS Array.fields/Array.struct SAMPLES \<========\< sample/a.rb \>========\> ~ \> cat sample/a.rb ``` require 'arrayfields' # # the class Array has only a few added method, one is for setting ``` the fields, # when the fields are set for an array THIS INSTANCE ONLY will be modified to # allow keyword access. other arrays will not be affected! # a = [0,1,2] fields = [‘zero’, ‘one’, ‘two’] a.fields = fields # ONLY the Array ‘a’ is affected! # # keyword access is now allowed for many methods # p a[‘zero’] #=\> 0 p a[‘one’] #=\> 1 p a[‘two’] #=\> 2 p a.at(‘one’) #=\> 1 p a.values\_at(‘zero’, ‘two’) #=\> [0, 2] # # assigmnet is allowed # a[‘zero’] = 42 p a[‘zero’] #=\> 0 a[‘zero’] = 0 # # assignment to non-fields results in the element being appended and the field # being added for future use (also appended) # p(a.fields.join(‘,’)) #=\> “zero, one, two” p a[‘three’] #=\> nil a[‘three’] = 3 p(a.fields.join(‘,’)) #=\> “zero, one, two, three” p a[‘three’] #=\> 3 # # other detructive methods are also keyword enabled # a.fill 42, ‘zero’, len = a.size p(a.values\_at(a.fields)) #=\> [42, 42, 42, 42] a.replace [0,1,2,3] ``` a.slice! 'two', 2 p a #=> [0,1] ``` ~ \> ruby sample/a.rb ``` 0 1 2 1 [0, 2] 42 "zero,one,two" nil "zero,one,two,three" 3 [42, 42, 42, 42] [0, 1] ``` \<========\< sample/b.rb \>========\> ~ \> cat sample/b.rb ``` require 'arrayfields' # # the struct/fields factory method can be used in much the same way ``` as ruby’s # own struct generators and is useful when the fields for a set of arrays is # known apriori # c = Array.fields :a, :b, :c # same as Array.struct a = c.new [42, nil, nil] a[:c] = 42 p a #=\> [42, nil, 42] # # of course we can append too # a[:d] = 42.0 p a[:d] #=\> 42.0 p a #=\> [42, nil, 42, 42.0] ~ \> ruby sample/b.rb ``` [42, nil, 42] 42.0 [42, nil, 42, 42.0] ``` AUTHOR removed\_email\_address@domain.invalid HISTORY 3.7.0: - multiton pattern clean up, thanks gavin kistner! - mods for ruby 1.8.6 (alias bug in 1.8.6 i think) - added PseudoHash class - added Array.struct/fields class generator enjoy. -a