Comparing object_id for float values?

Question

ruby

There is a code:

a = 0.1
b = 0.1
a.object_id == b.object_id

Is it true or false because different irb's produce different values?

Answer 1

Different versions of ruby? Ruby 2 optimized float

# Ruby 1.9
4.2.object_id == 4.2.object_id # => false

# Ruby 2.0
warn "Optimization only on 64 bit systems" unless 42.size * 8 == 64
4.2.object_id == 4.2.object_id # => true (4.2 is immediate)
4.2e100.object_id == 4.2e100.object_id # => false (4.2e100 isn't)