update: sorry, I fixed my program:
a = [ 'str1' , 'str2', 'str2', 'str3' ]
name = ''
a.each_with_index do |x, i |
if x == name
puts "#{x} found duplicate."
else
puts x
name = x if i!= 0
end
end
output:
str1
str2
str2 found duplicate.
str3
Is there another beautiful way in ruby
language to do the same thing ?
btw, actually. a
is a ActiveRecord::Relation
in my real case.
Thanks.
The problem you might have with each_cons
is that it iterates through n-1
pairs (if the length of the Enumerable is n
). In some cases this means you have to separately handle edge cases for the first (or last) element.
In that case, it's really easy to implement a method similar to each_cons
, but which would yield (nil, elem0)
for the first element (as opposed to each_cons
, which yields (elem0, elem1)
:
module Enumerable
def each_with_previous
self.inject(nil){|prev, curr| yield prev, curr; curr}
self
end
end