Unless unless

[Gábor SEBESTYÉN]

I have this very simple example:

a =3D 1
b =3D nil
puts a.nil?
puts b.nil?
puts "ok" unless a.nil? and b.nil?

Running it results these:

false
true
ok

Why the third answer is ok? Unless false and true =3D> false ..
Clue?

G=E1bor

 

[Renald Buter]

I have this very simple example:

a = 1
b = nil
puts a.nil?
puts b.nil?
puts "ok" unless a.nil? and b.nil?

Running it results these:

false
true
ok

Why the third answer is ok? Unless false and true => false ..

Just look carefully and mind that 'unless' is equivalent to 'if not'
a.nil? => false
b.nil? => true
false and true => false
if not false => if true

Regards,

Renald

 

[Robert Klemme]

I have this very simple example:

a = 1
b = nil
puts a.nil?
puts b.nil?
puts "ok" unless a.nil? and b.nil?

Running it results these:

false
true
ok

Why the third answer is ok? Unless false and true => false ..
Clue?

That's standard logic. Maybe this helps:
false
=> niltrue
=> nilok
=> nilok
=> nilok
=> nil

Kind regards

robert

 

[Gábor SEBESTYÉN]

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Just look carefully and mind that 'unless' is equivalent to 'if not'

Eee .. thanks ... need more coffee! )

G=E1bor=

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