Question

如果@ city.name不等于nil且＆＃34;＆＃34;则重定向到city_path;

如果@ city.name等于＆＃34;＆＃34;也重定向到city_path。如何解决？

if (@city.name != nil || @city.name != "")
      redirect_to city_path
      else
      render 'index'
    end

Answer 1

使用ternary operator和blank?方法的一行：

@city.name.blank? ? redirect_to(city_path) : render('index')

Answer 2

您可以使用present?方法处理For Ex: String S = AABCBBCB and K=1 If we delete 'B' at index 5 so String S = AABCBCB which is good string F[A]-F[A]=0 F[B]-F[A]=1 F[C]-F[B]=1 and so on和nil值

blank

Answer 3

您可以使用

 if @city.name.present?
      redirect_to city_path
      else
      render 'index'
    end

如果！= nil ||，请正确使用！=＆＃34;＆＃34; ROR

3 个答案: