what is this operator called and what is it used for <=>

Question

I recently came across this magical operator when digging into Groovy: <=>

Groovy has really made me happy with elvis operators ?. and ?: which I use constantly

Answer 1

Like many others mention, it's called the spaceship operator. Here's my test:

def a
def b

println 1 <=> 0                 // 1
println 0 <=> 1                 // -1
println 1 <=> a                 // 1
println b <=> 0                 // -1
println a <=> b                 // 0
println "abc" <=> "def"         // -1
println "abc" <=> 1             // throw exception: java.lang.ClassCastException