Linq style "For Each"

c# .net linq foreach
Stefan Steinegger picture Stefan Steinegger · Oct 2, 2009 · Viewed 405.8k times · Source

Is there any Linq style syntax for "For each" operations?

For instance, add values based on one collection to another, already existing one:

IEnumerable<int> someValues = new List<int>() { 1, 2, 3 };

IList<int> list = new List<int>();

someValues.ForEach(x => list.Add(x + 1));

Instead of 

foreach(int value in someValues)
{
  list.Add(value + 1);
}

Answer

Mark Seemann picture Mark Seemann · Oct 2, 2009

Using the ToList() extension method is your best option:

someValues.ToList().ForEach(x => list.Add(x + 1));

There is no extension method in the BCL that implements ForEach directly.

Although there's no extension method in the BCL that does this, there is still an option in the System namespace... if you add Reactive Extensions to your project:

using System.Reactive.Linq;

someValues.ToObservable().Subscribe(x => list.Add(x + 1));

This has the same end result as the above use of ToList, but is (in theory) more efficient, because it streams the values directly to the delegate.

Related questions

Update all objects in a collection using LINQ

Is there a way to do the following using LINQ? foreach (var c in collection) { c.PropertyToSet = value; } To clarify, I want to iterate through each object in a collection and then update a property on each object. My use …

Read More
LINQ query on a DataTable

I'm trying to perform a LINQ query on a DataTable object and bizarrely I am finding that performing such queries on DataTables is not straightforward. For example: var results = from myRow in myDataTable where results.Field("RowNo") == 1 select results; This …

Read More
Using LINQ to remove elements from a List<T>

Say that I have LINQ query such as: var authors = from x in authorsList where x.firstname == "Bob" select x; Given that authorsList is of type List<Author>, how can I delete the Author elements from authorsList that …

Read More