Confused with Ruby's <=> operator

Question

I am confused with Ruby's <=> operator. How does it differ from == or ===? Any comprehensive examples/use case? Thanks.

score 14 · Answer 1 · answered Jan 20 '11 at 10:49

14

<=> is the combined comparison operator. it returns 0 if LHS equals RHS, 1 if LHS is greater than the RHS and -1 if LHS is less than RHs

answered Jan 20 '11 at 10:49

ghostdog74

score 9 · Accepted Answer · edited May 23 '17 at 12:34

9

edited May 23 '17 at 12:34

Community

answered Jan 20 '11 at 10:47

Dogbert

how about in this code snippet, this confused me the most. assuming a = [ "d", "a", "e", "c", "b" ] how does this work, exactly? a.sort {|x,y| y <=> x } – arscariosus Jan 20 '11 at 11:02

score 2 · Answer 3 · answered Jan 20 '11 at 15:57

2

== will NOT work in sort for example

[3,5,6,2,7].sort{|x,y| x <=>y }

== returns Boolean
<=> returns Fixnum (-1,0,1)

answered Jan 20 '11 at 15:57

c2h2

1

I'm assuming -1 is the same as false, and 1 is the same as true. But how does it work in this example? – Ka Mok Jul 01 '16 at 23:57

3 Answers3