ruby on rails - Dynamically get all combinations of all elements of arrays -


important: can choose 1 element each array.

i'm writing code let me test quiz permutations. below current hardcoded way return array of possible permutations. need adapt dynamic, there more arrays added later.

i thinking of method accept array of options, , return array of permutations, brain breaks after first loop. appreciated. 

options = [   [["geek", "chef", "supporter", "fashionista"]],   [["0-1000", "1001-10000", "no limit"]],   [["many", "for one"]] ]   def test_gifts(options)   options.each_with_index |a,index|    ....   end end

hardcoded way:

character_types = ["geek","chef", "supporter", "fashionista"] price_ranges    = ["0-1,000","1,001-10000","no limit"] party_size      = ["many", "for one"]   permutations = [] character_types.each |type|   price_ranges.each |price|     party_size.each |party|       permutations << [type, price, party]     end       end end

which returns 

[["geek", "0-1,000", "many"], ["geek", "0-1,000", "for one"], ["geek", "1,001-10000", "many"], ["geek", "1,001-10000", "for one"], ["geek", "no limit", "many"], ["geek", "no limit", "for one"], ["chef", "0-1,000", "many"], ["chef", "0-1,000", "for one"], ["chef", "1,001-10000", "many"], ["chef", "1,001-10000", "for one"], ["chef", "no limit", "many"], ["chef", "no limit", "for one"], ["supporter", "0-1,000", "many"], ["supporter", "0-1,000", "for one"], ["supporter", "1,001-10000", "many"], ["supporter", "1,001-10000", "for one"], ["supporter", "no limit", "many"], ["supporter", "no limit", "for one"], ["fashionista", "0-1,000", "many"], ["fashionista", "0-1,000", "for one"], ["fashionista", "1,001-10000", "many"], ["fashionista", "1,001-10000", "for one"], ["fashionista", "no limit", "many"], ["fashionista", "no limit", "for one"]]

use array#product method this:

character_types.product(price_ranges, party_size)

to handle unknown number of other arrays:

arrays_to_permute = [character_types, price_ranges, party_size] first_array, *rest_of_arrays = arrays_to_permute first_array.product(*rest_of_arrays)

Comments

Post a Comment

Popular posts from this blog

Python Kivy ListView: How to delete selected ListItemButton? -

Image
i'm trying learn kivy building simple todo-list app suggested dusty phillips, author of book "creating apps in kivy". this code far: from kivy.app import app kivy.uix.boxlayout import boxlayout kivy.properties import objectproperty kivy.uix.listview import listitembutton class taskbutton(listitembutton): pass class todoroot(boxlayout): task_input = objectproperty() task_list = objectproperty() def add_task(self): self.task_list.adapter.data.extend([self.task_input.text]) self.task_list._trigger_reset_populate() def del_task(self): pass class todoapp(app): def build(self): return todoroot() if __name__ == '__main__': todoapp().run() and kv file: #: import main todo #: import listadapter kivy.adapters.listadapter.listadapter #: import listitembutton kivy.uix.listview.listitembutton todoroot: <todoroot>: orientation: "vertical" task_input: task_input_view t...
Read more

ruby - How do I merge two hashes into a hash of arrays? -

http://codepad.org/wmyzqlis i'd merge these 2 arrays: a = { :a => 'a', :b => 'b', :d => 'd' } b = { :a => '1', :b => 'b', :c => 'c' } into hash looks this: {:a => ["a", "1"], :b => ["b", "b"], :c => [nil, "c"], :d => ["d", nil] } this doesn't work: p a.merge(b) { |k, v1, v2| [v1, v2] } # {:c=>"c", :a=>["a", "1"], :b=>["b", "b"], :d=>"d"} it's because hash#merge call block duplicate keys. a = { :a => 'a', :b => 'b', :d => 'd' } b = { :a => '1', :b => 'b', :c => 'c' } hash[(a.keys|b.keys).map { |key| [key, [a.fetch(key, nil), b.fetch(key, nil)]] }] # => {:a=>["a", "1"], :b=>["b", "b"], :d=>["d", nil], :c=>...
Read more