How to refactor "if" statement into an "unless" statement?

Question

Is there any way to refactor this into an unless statement?

a = false
b = true

if !a or !b
  puts "hello world"
end

This doesn't seem to be equivalent

unless a or b
  puts "hello world"
end

Maybe try: `puts "hello world" unless (a || b)` – hwrdprkns Dec 29 '11 at 09:18 — hwrdprkns, Dec 29 '11 at 09:18

score 5 · Accepted Answer · answered Dec 29 '11 at 09:18

5

Negating your condition according to De Morgan's laws...

unless (a and b)

answered Dec 29 '11 at 09:18

Gishu

score 3 · Answer 2 · answered Dec 29 '11 at 09:17

3

That should be:

puts "hello" unless a and b

Or

unless a and b
   puts "hello"
end

answered Dec 29 '11 at 09:17

OscarRyz

Gumbo · Answer 3 · 2011-12-29T09:25:42.870

0

As unless is the negation of if, you need to negate the whole condition expression (you can use De Morgan’s laws to simplify it):

!(!a or !b) ≡ !!a and !!b ≡ a and b

So:

unless a or b
  puts "hello world"
end

edited Dec 29 '11 at 09:25

answered Dec 29 '11 at 09:18

Gumbo

3 Answers3