删除＆QUOT;重复对象和QUOT; [英] Removing "duplicate objects"

问题描述

让我们说我有来自同一类对象的数组，在这里关注的两个属性：名称和created_at

我如何找到数组中相同的名称（考虑的DUP）对象，然后删除数据库中的重复记录。与最近可created_at日期的对象，但是，是必须删除所述一个

解决方案

 看到= []
#sort通过创建日期和迭代
collection.sort（{| A，B | a.created_at＆LT; =＆GT; b.created_at}）。每做| OBJ |
  如果seen.map（安培;：名）.INCLUDE？如果该名称已被视为已经obj.name #check
    obj.destroy！
  其他
    可见＆LT;＆LT; OBJ＃如果不是，将其添加到阵列可见
  结束
结束
 

如果希望做的工作。

Let's say I have an array of objects from the same class, with two attributes of concern here: name and created_at.

How do I find objects with the same name (considered dups) in the array, and then delete the duplicate record in the database. The object with the most-recent created_at date, however, is the one that must be deleted.

解决方案

seen = []
#sort by created date and iterate
collection.sort({|a,b| a.created_at <=> b.created_at}).each do |obj| 
  if seen.map(&:name).include? obj.name #check if the name has been seen already
    obj.destroy!
  else
    seen << obj #if not, add it to the seen array
  end
end

Should do the job hopefully.

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