sorting multidimension array on secondary element where primary element is nil

Question

I have a multidimensional array where each array element in the primary array has two sub-elements and the second sub-element can sometimes be nil. I want to sort the primary array on the second sub-element, unless the second sub-element is nil, in which case I want the sort to look to the first sub-element for purposes of figuring out the order.

So, this data

[[7, nil], [5, 4], [3,9]]

would be sorted like this

[[5, 4], [7, nil], [3,9]]

Is there a way to do this?

Thanks!

Philip Hallstrom · Accepted Answer · 2012-11-14 18:09:38Z

3

1.8.7 > [[7, nil], [5, 4], [3,9]].sort_by{|a| a.last.nil? ? a.first : a.last}
 => [[5, 4], [7, nil], [3, 9]]

answered Nov 14, 2012 at 18:09

Philip Hallstrom

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1 Comment

mu is too short Over a year ago

{ |a| a.last || a.first } would an option if the sub-arrays only contain numbers and nils.

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