Boolean expression in Ruby - difference betwen or and ||

Question

Could someone please explain to me the differences of this two following lines of code?

puts false or true or false or false or false

I don't understand why the result of the execution of that line suppose to be different of:

puts false || true || false || false || false

I would be grateful if someone could explain that to me.

How many answers you want? Go here http://stackoverflow.com/search?q=%5Bruby%5D+%22%7C%7C%22+%22or%22 — Arup Rakshit, Oct 02 '13 at 13:24

score 2 · Accepted Answer · answered Oct 02 '13 at 13:37

2

p false or true #=> false => same as  (p false) or true
p false || true #=> true  => same as  p (false or true)

answered Oct 02 '13 at 13:37

hirolau

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score 0 · Answer 2 · answered Oct 02 '13 at 13:39

Ruby have inherited some of its control flow from Perl. So in Ruby and and or are for control flow, and && and || are boolean operators. This also means that and and or have higher precedence than && and ||

Ex:

and is used like:

 (true) and puts `true`

which is equivalent to

if true then
  puts "true"
end

and && should by used like:

true && false

which is false.

Boolean expression in Ruby - difference betwen or and ||

2 Answers2