Are there “rules” for Ruby syntactic sugar?

Question

I\'m learning the basics of Ruby (just starting out), and I came across the Hash.[] method. It was introduced with

a = [\"foo\", 1, \"bar\", 2]
=> [\"foo\", 1         


        

Answer 1

The * method tells ruby not to take the array as array, but to use the 'expanded' array.

Example:

def test(*argv)
  p argv
end

a = [1,2,3]
test(a) #-> [[1, 2, 3]]
test(*a) #-> [1, 2, 3]    

With test(a) the array a is the one and only parameter.

With test(*a) a is used as a list of parameters.

---

In your case

a = ["foo", 1, "bar", 2]
Hash[*a]

is similar to

Hash["foo", 1, "bar", 2]

Hash[*a] would be

Hash[["foo", 1, "bar", 2]]