C# foreach delete from list

Author: iktf

August undefined, 2024

WebThe second approach is a nice thought, but C# dictionaries are mutable and it's neither idiomatic nor efficient to copy them around if you can accomplish the same thing with mutation. This is a typical way: var itemsToRemove = myDic.Where(f => f.Value == 42).ToArray(); foreach (var item in itemsToRemove) myDic.Remove(item.Key); Web@vidstige Two options. 1) You can still call Update in this code. Nothing's stopping you. 2) Since it doesn't mutate the list, you could add a foreach(var e in enemyList)e.Update() before this code, which I would consider a better practice as it's a mutating operation, and I like to keep side effects out of anonymous methods like this, but that's just a personal …

Best way to iterate over a list and remove items from it?

WebJan 12, 2015 · Everyone else has posted "going backwards" answer, so I'll give the alternative: create a list of items you want to remove, then remove them at the end: List removals = new List (); foreach (string s in listBox1.Items) { MessageBox.Show (s); //do stuff with (s); removals.Add (s); } foreach (string s in … pen bé assérac

Remove elements from a list while iterating over it in C#

WebSep 18, 2013 · But the fact remains, depending on what you're doing there is more overhead with a foreach loop vs. a for loop. I just ran a quick test with your code with 100,000 entries in the List and the foreach loop took twice as long (actually 1.9 times as long). This isn't necessarily true in all situations, but in many. WebRemove elements from a list while iterating over it in C#. 1. Iterate Backwards. An elegant solution is to iterate backward in the list, which does not skip anything, and we can call the RemoveAt () method for ... 2. … WebAug 7, 2015 · Finally you would need to loop over the indexes to be deleted in reverse order and remove each from the original collection. list itemsToDelete for (int i = 0; i < items.Count; i++) { if (shouldBeDeleted (items [i])) { itemsToDelete.Add (i); } } foreach (int index in itemsToDelete.Reverse ()) { items.RemoveAt (i); } Share sktconnect

How to remove an item in a Generic List inside a foreach loop

c# - would remove a key from Dictionary in foreach cause a …

WebList has two methods you can use. RemoveAt (int index) can be used if you know the index of the item. For example: resultlist.RemoveAt (1); Or you can use Remove (T item): var itemToRemove = resultlist.Single (r => r.Id == 2); resultList.Remove (itemToRemove); When you are not sure the item really exists you can use SingleOrDefault. WebNov 28, 2014 · You cannot use a foreach to remove items during enumeration, you're getting an exception at runtime. You could use List.RemoveAll: list.RemoveAll (x => x.Number == 1); or, if it's actually not a List but any sequence, LINQ: list = list.Where (x => x.Number != 1).ToList (); skrillex quest gameWebOct 28, 2014 · You can't remove items from a collection while looping over it with an enumerator. Two approaches to solve this are: Loop backwards over the collection using a regular indexed for-loop (which I believe is not an option in the case of a HashSet); Loop over the collection, add items to be removed to another collection, then loop over the "to … pen auto st yrieix la perche

"WebApr 14, 2024 · Method 2: Using Split () and Distinct () Another way to remove duplicate words from a string in C# is to use the Split () method to split the string into an array of … " - C# foreach delete from list

C# foreach delete from list

How to remove items from a list while iterating in C# - iDiTect

WebSep 15, 2024 · In this article. In addition to taking items from a BlockingCollection by using the Take and TryTake method, you can also use a foreach ( For Each in Visual Basic) with the BlockingCollection.GetConsumingEnumerable to remove items until adding is completed and the collection is empty. This is called a mutating enumeration or … WebApr 14, 2024 · Method 2: Using Split () and Distinct () Another way to remove duplicate words from a string in C# is to use the Split () method to split the string into an array of words, then use the Distinct () method to remove duplicates, and finally join the array back into a string. Here's an example: string input = "C# Corner is a popular online ...

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WebJun 20, 2024 · 1) You can use a for/next loop instead a for/each. 2) You can iterate through a separate list: List custList = Customer.Populate (); foreach (var cust in custList.ToList ()) { custList.Remove (cust); } Notice the ToList on the list variable. WebJun 20, 2024 · 1) You can use a for/next loop instead a for/each. 2) You can iterate through a separate list: List custList = Customer.Populate (); foreach (var cust in …

WebSep 9, 2015 · So use a for-loop instead. for (int i = linelijst.count - 1; i >= 0; i--) { // linelijst [i] can be removed, etc. } Should be noted that when the item is removed you'd want to subtract one from the index so you don't skip anything, or if possible iterate from the end … WebIf you need to remove elements then you must iterate backwards so you can remove elements from the end of the list: var data=new List () {"One","Two","Three"}; for (int i=data.Count - 1; i > -1; i--) { if (data [i]=="One") { data.RemoveAt (i); } }

WebJul 13, 2024 · Using For/Foreach to Remove Elements From a Generic List The simplest solution is to do the same thing as in the naive example, only go backward with a for loop. We can then safely remove elements because they are being removed from the “end” of the List and do not affect the iteration: public static List ReverseIterate(List … WebApr 17, 2009 · The foreach statement is used to iterate through the collection to get the information that you want, but can not be used to add or remove items from the source collection to avoid unpredictable side effects. If you need to add or remove items from the source collection, use a for loop.

WebTo remove items from a list while iterating in C#, you should iterate through the list in reverse order. This ensures that you don't skip any elements and don't get an InvalidOperationException due to a modified collection. You can use a for loop with a decrementing index to achieve this.

WebApr 16, 2012 · foreach (Thing t in myCollection.Where(o=>shouldDelete(o)) { myCollection.Delete(t); } I don't understand why this fails. The "Where()" method obviously isn't returning the original collection, so I am not enumerating round the original collection when I try to remove something from it. penavayre sophieWebApr 11, 2024 · 一. 这里主要考虑两种参数类型:数组或者集合而这点区别主要体现在EmpMapper.xml文件中标签的collection属性: （1）当collection=”array“时,表名参数为数 … sktn comércioWebApr 18, 2016 · If you want to remove in range (not in the entire list ), just modify for loop: // No Enumarable.Range (1, 10) - put them into "for" for (int i = Math.Min (11, safePendingList.Count - 1); i >= 1; --i) if (condition) safePendingList.RemoveAt (i); Or if you have to remove items in forward looping: sktc main street emailWeba foreach (item in list) construct allows you to use break or continue if you need to exit the iteration or the loop. But you cannot alter the list inside a foreach loop. I'm surprised to see that list.ForEach is slightly faster. But that's probably not a valid reason to use it throughout , that would be premature optimisation. penbbs 469 double nib fountain penWebAug 24, 2015 · foreach (int index in myListBox.SelectedIndices.Cast ().Select (x => x).Reverse ()) myListBox.Items.RemoveAt (index); Basically the same as Patrick's solution of iterating backwards and removing selected items. However instead of iterating backwards, we reverse the list of items to remove and iterate forwards. pen cartilageWebMay 17, 2009 · 1) In your foreach-loop, save a list of all elements that should be removed. Then you loop through just those elements and remove them. 2) Use an ordinary for-loop and keep track of which is the next element to visit after you have deleted one item. Edit: When using a for-loop do it the way Fredrik suggests, looping backwards. Share Follow pena x series front flipperWebMay 7, 2009 · This creates a new list that you perform ForEach on, therefore you can remove your original list, yet keep iterating through the entire list. List Os = ....; Os.ToList ().ForEach ( delegate (Type o) { if (!o.cond) Os.Remove (o); } ); SOLUTION - Regular foreach: This technique also works for regular foreach statements. penavayre vacquiers