使用Linq或Lambda表达式检查复杂对象中的重复项 [英] Checking for duplicates in a complex object using Linq or Lambda expression

问题描述

我刚刚开始学习linq和lambda表达式，它们似乎非常适合在复杂的对象集合中查找重复项，但是我有些困惑，希望有人可以帮助我重新走上正轨进行快乐的编码.

I've just started learning linq and lambda expressions, and they seem to be a good fit for finding duplicates in a complex object collection, but I'm getting a little confused and hope someone can help put me back on the path to happy coding.

我的对象的结构类似于list.list.uniqueCustomerIdentifier

My object is structured like list.list.uniqueCustomerIdentifier

我需要确保在整个复杂对象中没有重复的uniqueCustomerIdentifier.如果有重复项，我需要确定哪些重复项并返回重复项列表.

I need to ensure there are no duplicate uniqueCustomerIdentifier with in the entire complex object. If there are duplicates, I need to identify which are duplicated and return a list of the duplicates.

推荐答案

• 解开层次结构
• 将每个元素投影到其uniqueID属性
• 对这些ID进行分组
• 按元素多于1个的组过滤组
• 将每个组投影到该组的键(返回到uniqueID)
• 枚举查询并将结果存储在列表中.
• Unpack the hierarchy
• Project each element to its uniqueID property
• Group these ID's up
• Filter the groups by groups that have more than 1 element
• Project each group to the group's key (back to uniqueID)
• Enumerate the query and store the result in a list.

var result = 
  myList
    .SelectMany(x => x.InnerList)
    .Select(y => y.uniqueCustomerIdentifier)
    .GroupBy(id => id)
    .Where(g => g.Skip(1).Any())
    .Select(g => g.Key)
    .ToList()

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