Rational numbers not behaving like fractions in algebra with Ruby

Question

Can someone please explain this to me?

x = Rational(3/4) * 8
 => (0/1) # I Expected it to return 6
x.to_i
 => 0

Thanks.

I think you want `x = Rational(3, 4) * 8` – Blake Taylor Aug 21 '12 at 01:59 — Blake Taylor, Aug 21 '12 at 01:59

score 5 · Accepted Answer · answered Aug 21 '12 at 02:08

5

You are creating a Rational number with 3/4 as the only argument. 3/4 is 0, so, your code is equivalent to

Rational(0) * 8

which obviously is 0.

Compare this to

Rational(3, 4) * 8
# => (6/1)

where you explicitly pass both the numerator and denominator.

answered Aug 21 '12 at 02:08

Jörg W Mittag

score 1 · Answer 2 · answered Jul 28 '13 at 17:22

1

If you prefer having slashes in the fractions, you may use strings as arguments:

x = Rational('3/4') * 8

or

x = ('3/4'.to_r) * 8

answered Jul 28 '13 at 17:22

野上上部

2 Answers2