Question

print (-1 == -1) and (myobj.nil?)

true

print (-1 == -1) && (myobj.nil?)

false

Note, myobj.nil? returns false
so, should not this always be false.

Answer 1

Because they have different operator precedence.

The first evaluates as:

(print (-1 == -1)) and (myobj.nil?)

It prints true, because -1 == -1, then print returns nil and nil and false is nil.

The second is equivalent to:

print ((-1 == -1) && (myobj.nil?))

It prints (true && false), which is false, then print returns nil.