Passing nil arguments into methords in ruby

Question

Is there any way I can make ruby method that does something even if given X number of arguments and excepted more than X number of arguments?

For example:

def greet (name)
  name != nil ? "Hello, ${name}!" : "Hello!"
end

print greet()

should return "Hello!"

Smth like `def greet (name = nil)`? – Aleksei Matiushkin Apr 11 '17 at 04:34 — Aleksei Matiushkin, Apr 11 '17 at 04:34
Do you mean this could take any number of names? – tadman Apr 11 '17 at 06:50 — tadman, Apr 11 '17 at 06:50

score 1 · Accepted Answer · answered Apr 11 '17 at 05:51

Whether one wants to cover any amount of arguments, they usually use splat parameter:

def greet(*params)
  case params.size
  when 0 then "Hello!"
  when 1 then "Hello, #{params.first}!"
  else "Hello, ya all there!"
end

or:

def greet(*params)
  name, = params
  name.nil? ? "Hello!" : "Hello, #{name}!"
end

score 1 · Answer 2 · edited May 23 '17 at 12:09

1

So, if you want to pass n-number of arguments, you can do it with *args (which will translate it as a list of arguments)

def test(*args)
  args.empty? "if true something" : "if false something"
end

P.S. You can read more about it here

edited May 23 '17 at 12:09

Community

1
1

answered Apr 11 '17 at 05:51

score 0 · Answer 3 · edited Apr 11 '17 at 04:37

0

I would do:

def greet(name = nil)
  name ? "Hello, #{name}!" : "Hello!"
end

>> greet("Joe")
#⇒ "Hello, Joe!"
>> greet
#⇒ "Hello!"

edited Apr 11 '17 at 04:37

Aleksei Matiushkin

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answered Apr 11 '17 at 04:35

moveson

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This answer hardly covers “X number of arguments,” but it’s really hard to understand the exact statement of OP. – Aleksei Matiushkin Apr 11 '17 at 04:37
I interpolated X == 0. – moveson Apr 11 '17 at 04:50

score 0 · Answer 4 · answered Apr 11 '17 at 09:27

Here's a simple method which should work any number of arguments :

def greet(*names)
  ['Hello', *names].join(', ') + '!'
end

puts greet
# Hello!
puts greet('John')
# Hello, John!
puts greet('Jane', 'John')
# Hello, Jane, John!

You could add some more logic to display "Hello, Jane, John & Jack!".

Passing nil arguments into methords in ruby

4 Answers4