Converting an empty string to nil in place?

Question

I'm looking for a way to convert an empty string to nil in place using Ruby. If I end up with a string that is empty spaces I can do

 "    ".strip! 

This will give me the empty string "".

What I would like to be able to do is something like this.

"    ".strip!.to_nil! 

This will get an in place replacement of the empty string with nil. to_nil! would change the string to nil directly if it is .empty? otherwise if the string is not empty it would not change.

The key here is that I want it to happen directly rather than through an assignment such as

f = nil if f.strip!.empty? 

Answer 1

The clean way is using presence.

Let's test it.

'    '.presence # => nil   ''.presence # => nil   'text'.presence # => "text"   nil.presence # => nil   [].presence # => nil   {}.presence # => nil  true.presence # => true  false.presence # => nil 

Please note this method is from Ruby on Rails v4.2.7 https://apidock.com/rails/Object/presence

Answer 2

That isn't possible.

String#squeeze! can work in place because it's possible to modify the original object to store the new value. But the value nil is an object of a different class, so it cannot be represented by an object of class String.