Question

I have a method like this:

def foo(fruit='apple', cut='sliced', topping='ice cream')   # some logic here end 

How can I call it where I only override the topping parameter but use the default values for the others, something like this

foo('','','hot fudge') 

Of course this does not work as intended, but I want to only provide a value for the third optional parameter, and have the first two stick with their default values. I know how to do this with a hash, but is their a shortcut way to do it, using the above syntax?

Answer 1

You can’t use this syntax to do this in ruby. I would recommend the hash syntax for this.

def foo(args={})   args[:fruit]    ||= 'apple'   args[:cut]      ||= 'sliced'   args[:topping]  ||= 'ice cream'   # some logic here end  foo(:topping => 'hot fudge') 

You could also do this using positional arguments:

def foo(fruit=nil,cut=nil,topping=nil)   fruit    ||= 'apple'   cut      ||= 'sliced'   topping  ||= 'ice cream'   # some logic here end  foo(nil,nil,'hot fudge') 

Bear in mind that both of these techniques prevent you from passing actual nil arguments to functions (when you might want to sometimes)