CODEWITHSUNDEEP
rubypointersmethods
Ben D
Ben D

Reputation: 475

What is the difference between these two method parameter definitions?

I'm starting to learn Ruby. I read that arguments where passed by reference to a method, however I don't understand the difference between these two methods.

def print(text)
   puts text
end

and

def print(*text)
    puts text
end

Using a * means that we are passing a pointer like in C?

Upvotes: 2

Views: 179

Answers (4)

Douglas G. Allen
Douglas G. Allen

Reputation: 2261

First you have two nice methods started there. But I would say try to avoid using puts inside them. You don't need it anyway. A method will always yield the last statement evaluated. something = text would get the job done. And I don't need to answer now about the differences. Your first two replies are very good there. But you may want to try something like this j = *[] #=> nil in 1.8 but [] in 1.9 It's been the new kid on the block for a time now. Guess what it does?

Upvotes: 0

Michael Kohl
Michael Kohl

Reputation: 66837

There are no pointers in Ruby, * in this context is generally referred to as the "splat" operator:

In this case the method can take an arbitrary number of arguments, which will be available in the array text.

Upvotes: 2

dj2
dj2

Reputation: 9618

The *text is what's called the splat operator in Ruby. It basically means if you pass multiple arguments to the second print they will get slurped into the single text variable.

See The Splat Operator in Ruby

Upvotes: 5

wkl
wkl

Reputation: 79961

The * before a parameter name in a Ruby parameter list is used for variable length arguments, so they are similar to the ... in C/C++ for varargs.

def vlaFunc(*args)
    puts args
end

vlaFunc(1,2,3)

# output is [1,2,3]

Upvotes: 4

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