> 1)
> I would like to create an array of n empty arrays, i.e.

> [ [], [], ... n-3 []'s, [] ]

> So that the inner arrays are different objects.

> Array.new(n,[]) does not help since the created arrays are not different
> objects.

> Is there an idiomatic way to accomplish this?

> 2) Is there an idiomatic way to do this (in a generic way, of course):

> some_func(
> [1,2,3]
> [4,5,6]
> [7,8,9] )

> => [ [1,4,7], [2,5,8], [3,6,9] ]

>> some_func(
>> [1,2,3]
>> [4,5,6]
>> [7,8,9] )

>> => [ [1,4,7], [2,5,8], [3,6,9] ]
> [1,2,3].zip([4,5,6],[7,8,9]) # => [[1,4,7], [2,5,8], [3,6,9]]

> Thx!

>>> 2) Is there an idiomatic way to do this (in a generic way, of course):

>>> some_func(
>>> [1,2,3]
>>> [4,5,6]
>>> [7,8,9] )

>>> => [ [1,4,7], [2,5,8], [3,6,9] ]
>> [1,2,3].zip([4,5,6],[7,8,9]) # => [[1,4,7], [2,5,8], [3,6,9]]

> Sorry, I did not describe the scenario properly.
> The thing is that I am iterating over an array (of arrays)
> and I don't have the all the arrays at once (the inner arrays are
> generated on the fly). Let me illustrate it:

> input = [ [1,2,3], [4,5,6], [7,8,9] ]
> result = []

> input.each { |i| do_something_with(result, i) }

> and the result should be

> [ [1,4,7], [2,5,8], [3,6,9] ]

> The question sounds: how is do_something_with implemented?
> I have already implemented it but I don't think so it's a state-of-the
> art solution ;)

> > 1)
> > I would like to create an array of n empty arrays, i.e.

> > [ [], [], ... n-3 []'s, [] ]

> > So that the inner arrays are different objects.

> > Array.new(n,[]) does not help since the created arrays are not different
> > objects.

> > Is there an idiomatic way to accomplish this?
> a = (0..3).collect{[]} # => [[], [], [], []]
> a[0][0] = 1
> a # => [[1], [], [], []]

> input.each { |i| do_something_with(result, i) }

> and the result should be

> [ [1,4,7], [2,5,8], [3,6,9] ]

> The question sounds: how is do_something_with implemented?
> I have already implemented it but I don't think so it's a state-of-the
> art solution ;)

> input.each{|i| i.each_with_index{|x,j| (result[j] ||= []) << x}}

> Not sure if it'll play the way you want with variable-length arrays, but
> it puts the right contents in result.

>> You are simply brilliant ;)

> I am certainly very far from that... I was just happy that (still being
> a noob) I have solved something on my own for the first time. What's
> wrong with that?