C Remove object from list of objects

Question

I have a list of objects and I am trying to remove a specific object in the list by first checking a property in the object   Originally I used a foreach but then realised you can t use this while modifying a collection  so I decided to use a normal for but then I m not sure how to write code that does what I originally wrote   How do I go about writing code to do what I originally had   Thanks  Here s my code       public void DeleteChunk int ChunkID                  foreach  Chunk i in ChunkList                            if  i UniqueID    ChunkID                                    ChunkList Remove i                                          This won t work because here i is just an integer so i UniqueID won t exist          for  int i   0  i  lt  ChunkList Capacity  i                          if  i UniqueID    ChunkID                                ChunkList Remove i

User · Answer

There are two problems with this code    Capacity represents the number of items the list can contain before resizing is required  not the actual count  you need to use Count instead  and When you remove from the list  you should go backwards  otherwise you could skip the second item when two identical items are next to each other

User · Answer

You re checking i s UniqueID while i is actually an integer  You should do something like that  if you want to stay with a for loop   for  int i   0  i  lt  ChunkList Capacity  i          if  ChunkList i  UniqueID    ChunkID                ChunkList Remove i             You can  and should  however  use linq   ChunkList Remove x   gt  x UniqueID    ChunkID

User · Answer

You re removing and then incrementing  which means you ll be one ahead of yourself   Instead  remove in reverse so you never mess up your next item   for  int i   ChunkList Count-1  i  gt  0  i--        if  ChunkList i  UniqueID    ChunkID                ChunkList RemoveAt i

User · Answer

Simplest solution without using LINQ       Chunk toRemove   null      foreach  Chunk i in ChunkList                if  i UniqueID    ChunkID                        toRemove   i              break                      if  toRemove    null            ChunkList Remove toRemove            If Chunk is a struct  then you can use Nullable lt Chunk gt  to achieve this

User · Answer

One technique is to create a copy of the collection you want to modify  change the copy as needed  then replace the original collection with the copy at the end

User · Answer

Firstly  you are using Capacity instead of Count   Secondly  if you only need to delete one item  then you can happily use a loop  You just need to ensure that you break out of the loop after deleting an item  like so   int target   4   for  int i   0  i  lt  list Count    i        if  list i  UniqueID    target                list RemoveAt i           break            If you want to remove all items from the list that match an ID  it becomes even easier because you can use List lt T gt  RemoveAll Predicate lt T gt  match   int target   4   list RemoveAll element   gt  element UniqueID    target

User · Answer

You can simplify this with linq   var item   ChunkList SingleOrDefault x   gt  x UniqueId    ChunkID   if  item    null      ChunkList Remove item     You can also do the following  which will also work if there is more than one match   ChunkList RemoveAll x   gt  x UniqueId    ChunkID

User · Answer

Originally I used a foreach but then realised you can t use this while modifying a collection   You can create a copy of the collection and iterate over that using ToList   to create to copy    foreach Chunk chunk in ChunkList ToList            if  chunk UniqueID    ChunkID                  ChunkList Remove chunk

User · Answer

First you have to find out the object in the list  Then you can remove from the list          var item   myList Find x  gt x ItemName    obj ItemName          myList Remove item

User · Answer

If ChunkList is List lt Chunk gt   you can use the RemoveAll method   ChunkList RemoveAll chunk   gt  chunk UniqueID    ChunkID

User · Answer

You can use a while loop to delete item items matching ChunkID  Here is my suggestion   public void DeleteChunk int ChunkID       int i   0     while  i  lt  ChunkList Count              Chunk currentChunk   ChunkList i         if  currentChunk UniqueID    ChunkID             ChunkList RemoveAt i                 else           i

[c#] C# Remove object from list of objects

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