How to Check if a Variable is Defined?
August 13, 2021 in ruby
defined? expression allows you to test if a variable is defined or not. If it isn’t defined, it returns
nil. Otherwise, it returns a string that provides information about the variable.
> defined? a => nil > a = 10 => 10 > defined? a => "local-variable" > defined? nil => "nil" > defined? Array => "constant" > defined? String => "constant" * class Person > end > defined? Person => "constant" > defined? 10 => "expression"
A variable set to
nil is also initialized.
> b = nil => nil > defined? b => "local-variable"