Feature #4633
closed
iterate method / extended version of for
Description
=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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