Operator <=> in Ruby [duplicate]

Question

Possible Duplicate:
What is the Ruby <=> (spaceship) operator?

I saw a code and an operator I'm unfamiliar with

 @array << {:suffix=> substring, :index => i}
 @array.sort! { |x,y| x[:suffix] <=> y[:suffix]}

I can't do google on it. What does <=> do?

Answer 1

This is the spaceship operator, it was borrowed from Perl. It is commonly used for sorting, because it returns -1 if left operand is less than right operand, 1 if right operand is greater than the left and returns 0 otherwise.

1 <=> 2 # => -1
2 <=> 1 # => 1
1 <=> 1 # => 0

Answer 2

It does comparison defined for the particular class. If it is the case that ... < ... is true, it returns -1, if ... == ... is true, then 0, and if ... > ... is true, then 1.