Rails 5：ActiveRecord集合index_by

使用索引方法將應用升級到Rails 5。問題在於它沒有遞增到下一個ActiveRecord集合記錄。下面的代碼用於在Rails 4.0中工作。試着用index_by。Rails 5：ActiveRecord集合index_by

def next_question 
    index = campaign.quiz_questions.index self 
    campaign.quiz_questions[index + 1] 
end

調試器

(byebug) campaign.quiz_questions.index 
*** NoMethodError Exception: undefined method `index' for #<QuizQuestion::ActiveRecord_Associations_CollectionProxy:0x007f80012d71b0> 
Did you mean? index_by

使用index_by

(byebug) index = campaign.quiz_questions.index_by 
#<Enumerator: #<ActiveRecord::Associations::CollectionProxy [#<QuizQuestion id: 113, campaign_id: 492, message: "Where did Hullabalooza's freak show manager send H...", created_at: "2016-07-20 20:50:32", updated_at: "2016-07-20 20:50:32">]>:index_by>

指數+ 1

(byebug) index + 1 
*** NoMethodError Exception: undefined method `+' for #<Enumerator:0x007fc4db445960> 

nil

來源

2016-07-20 khoamle

它改變爲find_index方法。現在它正在工作

def next_question 
    index = campaign.quiz_questions.find_index self 
    campaign.quiz_questions[index + 1] 
end

來源

2016-07-25 20:37:21 khoamle

Rails 5：ActiveRecord集合index_by

回答

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