How I can check if an object is null in ruby on rails 2?

Solution 1:

it's nilin Ruby, not null. And it's enough to say if @objectname to test whether it's not nil. And no then. You can find more on if syntax here:

http://en.wikibooks.org/wiki/Ruby_Programming/Syntax/Control_Structures#if

Solution 2:

You can check if an object is nil (null) by calling present? or blank? .

@object.present?

this will return false if the project is an empty string or nil .

or you can use

@object.blank?

this is the same as present? with a bang and you can use it if you don't like 'unless'. this will return true for an empty string or nil .

Solution 3:

Now with Ruby 2.3 you can use &. operator ('lonely operator') to check for nil at the same time as accessing a value.

@person&.spouse&.name

https://en.wikibooks.org/wiki/Ruby_Programming/Syntax/Operators#Other_operators

Use #try instead so you don't have to keep checking for nil.

http://api.rubyonrails.org/classes/Object.html#method-i-try

@person.try(:spouse).try(:name)

instead of

@person.spouse.name if @person && @person.spouse