From: Colin Bartlett <colinb2r@...>
Date: 2009-10-25T19:26:29+09:00
Subject: Re: convert/replace a value of nil with 0?

More possibilities?

(1) If you just want an array "accessor" without changing the array itself
and without setting up a new array, then adapting Jesús Gabriel y Galán's post:

class Object
  def nil_to( value ); self.nil? ? value : self ; end
end
a[5] = nil ; a[5].nil_to( 0 )  #=> 0
a[7] = false ; a[7].nil_to( 0 )  #=> false

or even:

class Array
  def at_with_nil_to(i, value); (obj = self[i]).nil? ? value : obj; end
end

(2) If you want to modify the array itself, instead of creating a new array,
then adapting Rajinder Yadav's post you can do:
  arr.collect! { |obj| obj.nil? ? 0 : obj }
or use "map!" which is a synonym for "collect!".
Using "collect!" seems to be faster than using "each_with_index"
and modifying the appropriate elements. Is that what people would expect?
I ask because for similar things which modified arrays "in place"
I used to use "each_with_index" type code until I understood what
collect!/map! did.