Ruby » Ruby master

Feature #4633

Updated by mame (Yusuke Endoh) almost 13 years ago

=begin 
 
 The Ruby world is known for using each, but it does not always look nice (although in most cases it does). 

 I am proposing an iterate method that is nicely readable and allows easy iteration over multiple objects. It behaves like each for an single argument, but passes nils for Enumerables with multiple sizes: 
   iterate [1,2], [3,4,5] do |e,f| 
     puts "#{e},#{f}" 
   end 
   # outputs 
   #    1,3 
   #    2,4 
   #    ,5 

 A simple Ruby implementation: 
   def iterate(*params) 
     # params.shift.zip(*params).each{ |*elements| yield *elements } 
     raise ArgumentError, "wrong number of arguments (0)" if params.empty? 

     first = params.shift 
     if params.empty? # single param - like each 
       if block_given? 
         first.map{|e| yield e } 
       else 
         first.map.to_enum 
       end 
     else # multiple params 
       max_size = [first, *params].max_by(&:count).size 
       padded_first = first.to_a + [nil]*(max_size - first.count)    # append nils 
       obj = padded_first.zip *params 
       if block_given? 
         obj.map{|es| yield *es } 
       else 
         obj.map.to_enum 
       end 
     end 
   end 

 A modified version of this request (no new method/statement) could be an alternative usage of for, something like: 
   for e,f in [1,2], [3,4,5] 
     puts "#{e},#{f}" 
   end 
   # outputs 
   #    1,3 
   #    2,4 
   #    ,5 

 This feature request does not add something needed, but I think, Ruby would look even more beautiful. 
 
 =end 
 

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