Why do Ruby's default parameter values not get assigned to nil arguments?

Question

I'm new to Ruby and came across something that confused me a bit.

I set a default parameter value in a method signature.

When calling the method, I passed a nil argument to that parameter.

But the default value wasn't assigned; it remained nil.

# method with a default value of 1000 for parameter 'b' def format_args(a, b=1000)   "\t #{a.ljust(30,'.')} #{b}" end  # test hash dudes = {}; dudes["larry"] = 60 dudes["moe"] = nil  # expecting default parameter value puts "Without nil check:" dudes.each do |k,v|       puts format_args(k,v) end  # forcing default parameter value puts "With nil check:" dudes.each do |k,v|       if v      puts format_args(k,v)   else      puts format_args(k)   end end 

Output:

Without nil check:      larry......................... 60      moe...........................  With nil check:      larry......................... 60      moe........................... 1000 

Is this expected behavior?

What ruby-foo am I missing?

Seems like nil isn't the same "no value" that I'm accustomed to thinking of null in other languages.

Answer 1

The default parameter is used when the parameter isn't provided.

If you provide it as nil, then it will be nil. So yes, this is expected behavior.