CODEWITHSUNDEEP
ruby-on-railsdatetimecontroller
Skylive
Skylive

Reputation: 37

rails : undefined method `>' for nil:NilClass

I'm a beginner in rails and I need to compare 2 DateTime on my controller :

@b = Book.find(params[:book][:id])
if @b.expiry_date > DateTime.now
  ... something here ...
end

But I get this error :

undefined method `>' for nil:NilClass

Anyone have an idea why ?

Upvotes: 0

Views: 2386

Answers (2)

Anthony E
Anthony E

Reputation: 11235

Operators are methods in ruby, so your undefined method '>' for nil:NilClass error indicates that @b.expiry_date is nil on this line: if @b.expiry_date > DateTime.now.

You can use a short-circuiting logic to only evaluate the condition if @b.expiry_date is present.

if @b.expiry_date && (@b.expiry_date > DateTime.now)

The if expressions is only true if both sides of the && are also true, so(@b.expiry_date > DateTime.now) won't be executed if the first condition, @b.expiry_date, is false or nil.

Otherwise, you'll need to add logic/validations to ensure the existence of expiry_date.

Upvotes: 3

bkunzi01
bkunzi01

Reputation: 4561

Just add a check that the record isn't nil in your if statement as shown: 

    @b = Book.find(params[:book][:id])
      if [email protected]_date.nil? && @b.expiry_date > DateTime.now
      ... something here ...
    end

If all Books are supposed to have expiry dates you should add a validation that insists an expiry date is included when creating/updating a Book record in your Book Model!

Upvotes: 0

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