Quick and dirty nil and empty string handling in Ruby

02 Jun 2015 I've run across issues with empty strings and nil values quite a bit lately - seems like mostly in relation to an API interfacing with iOS. Here are two quick tips:

To ensure that no nil values are given, I can call .to_s on any string values or values that should be strings. If one of them is nil, it will convert it to an empty string. If it's already a string, it will just leave it alone.

How about going the other way? .presence is the key. Call .presence on an empty string and it will give back nil. If the string isn't empty it will return the original string.

TL;DR:


"".presence 
# => nil 

"hey".presence 
# => "hey" 

nil.to_s 
# => ""

"hey".to_s 
# => "hey"