Most of the Query Operators Execute only when they are enumerated(IEnumerator Type-Move Next),but not when constructed.
var item = new List<int>();
item.Add(2);
IEnumerable<int> result = item.Select(x => x*5);
//Query is Constructed
item.Add(3);
//But still the item will be added and output would be 10,15 instead of 10.
//This is called deferred execution.Query executes only on enumerating(for-each) but not on construction.
foreach (var VARIABLE in result)
{
Console.WriteLine(VARIABLE);
}
Note: Not All Query Operators involves Deferred Execution.For instance First Operator should Execute the Query when constructed and return the First Element.
