如何减少多个嵌套的foreach块 [英] How to reduce multiple nested foreach blocks

问题描述

我有以下情况：

  var Ids = object1.GetIds（）; //返回IEnumerable< int> 
 foreach（Ids中的var id）
 {
 foreach（object1.GetRelatedObjects（id）中的var relatedObject）
 {
 //做某事与相关的对象
 
 
 
 
 
 
 $ b在这种情况下，我想摆脱第一个foreach并将这个逻辑简化为单一的foreach。如何才能实现这一点？
 
 
 
应该可以用LINQ表达一些类似的方法吗？
 
解决方案
 
当两个循环之间没有任何内容时，在嵌套之前或之后，可以使用 SelectMany 将两个循环扁平化 / p> 
 
 
  foreach（Ids.SelectMany（object1.GetRelatedObjects）中的var relatedObject）{
 ... 
} 
  
这个循环与循环之间的一个主要区别是 id 不在范围之内。假设 relatedObject 暴露了一个public  Id 属性，这在你的情况下不应该是一个问题，因为你可以提取 id 返回 
 
 
  var id = relatedObject.Id; 
  
 
I have the following scenario:
var Ids = object1.GetIds(); // returns IEnumerable<int>
foreach (var id in Ids)
{
    foreach (var relatedObject in object1.GetRelatedObjects(id))
    {
    // Do Something with related object
    }
}
In this case, i want to get rid of from the first foreach and reduce this logic into single foreach. How could i achieve this?


Should it be possible with LINQ expression some similar methodology?
解决方案
When there is nothing between the two loops, before or after the nested one, you can use SelectMany to "flatten" two loops into one:
foreach (var relatedObject in Ids.SelectMany(object1.GetRelatedObjects)) {
    ...
}
One major difference between this loop and the loop that you have is that id is no longer in scope. Assuming that relatedObject exposes a public Id property, this should not be a problem in your situation, because you could extract the id back with
var id = relatedObject.Id;


                        
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