Modify collection inside foreach

  • You cannot modify a collection inside a foreach method.
  • Below is one of the way to modify the collection.
    • Use select to modify and give us a new list.
    • Assign back to the existing collection. 
				
					
var numCollection = new List<int>() { 6, 12, 24 };
try
{
    for (int i = 4; i < 12;)
    {
        var list = numCollection.Select(a => a - i);
        numCollection = list.ToList();
        i = i + 4;
    }
}
catch (Exception)
{

}
				
			

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