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GeneralRe: necessity to use .Any() to check if an IEnumerable<T> result has no items without iterating over it ? Pin
Richard Deeming16-Jan-22 22:45
mveRichard Deeming16-Jan-22 22:45 
GeneralRe: necessity to use .Any() to check if an IEnumerable<T> result has no items without iterating over it ? Pin
BillWoodruff18-Jan-22 1:19
mveBillWoodruff18-Jan-22 1:19 
GeneralRe: necessity to use .Any() to check if an IEnumerable<T> result has no items without iterating over it ? Pin
Richard Deeming18-Jan-22 1:41
mveRichard Deeming18-Jan-22 1:41 
GeneralRe: necessity to use .Any() to check if an IEnumerable<T> result has no items without iterating over it ? Pin
BillWoodruff18-Jan-22 3:08
mveBillWoodruff18-Jan-22 3:08 
GeneralRe: necessity to use .Any() to check if an IEnumerable<T> result has no items without iterating over it ? Pin
Richard Deeming18-Jan-22 6:17
mveRichard Deeming18-Jan-22 6:17 
GeneralRe: necessity to use .Any() to check if an IEnumerable<T> result has no items without iterating over it ? Pin
BillWoodruff19-Jan-22 13:58
mveBillWoodruff19-Jan-22 13:58 
GeneralRe: necessity to use .Any() to check if an IEnumerable<T> result has no items without iterating over it ? Pin
Richard Deeming19-Jan-22 21:43
mveRichard Deeming19-Jan-22 21:43 
GeneralRe: necessity to use .Any() to check if an IEnumerable<T> result has no items without iterating over it ? Pin
BillWoodruff20-Jan-22 4:26
mveBillWoodruff20-Jan-22 4:26 
We may not end up eye=>to<=eye on this one ... of course, on a practical level, we both use IEnumerable with skill (for most of us it takes some time to achieve a sense of mastery).

Let me ask you to imagine you are teaching a bright young person how to use Linq: they ask you, one day: "what is an IEnumerable before it gets iterated ?" ... what metaphor, or analogy, would you use to communicate your understanding ?

I run a Linq operator on a collection that returns an IEnumerable<T>: I get a result which is a ""System.Linq.Enumerable+WhereListIterator`1[[System.Int32, System.Private.CoreLib" ... I call that an instance of a special object, a kind of "alternate reality" with some unique methods ('MoveNext, etc. and facilities (deferred execution.

List<int> ints0 = new List<int>() { 1, 2, 3, 4, 5, 6, 7, 8 };
var ienm = ints0.Where(itm => itm > 2);
I examine the Type:

> ? ienm.GetType()
{Name = "WhereListIterator`1" FullName = "System.Linq.Enumerable+WhereListIterator`1[[System.Int32, System.Private.CoreLib, Version=5.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e]]"}
    Assembly: {System.Linq, Version=5.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a}
    AssemblyQualifiedName: "System.Linq.Enumerable+WhereListIterator`1[[System.Int32, System.Private.CoreLib, Version=5.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e]], System.Linq, Version=5.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a"
    Attributes: NestedPrivate | Sealed | BeforeFieldInit
    BaseType: {Name = "Iterator`1" FullName = "System.Linq.Enumerable+Iterator`1[[System.Int32, System.Private.CoreLib, Version=5.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e]]"}

«The mind is not a vessel to be filled but a fire to be kindled» Plutarch


modified 20-Jan-22 10:33am.

GeneralRe: necessity to use .Any() to check if an IEnumerable<T> result has no items without iterating over it ? Pin
harold aptroot16-Jan-22 22:48
Memberharold aptroot16-Jan-22 22:48 
GeneralRe: necessity to use .Any() to check if an IEnumerable<T> result has no items without iterating over it ? Pin
BillWoodruff18-Jan-22 0:49
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GeneralRe: necessity to use .Any() to check if an IEnumerable<T> result has no items without iterating over it ? Pin
jschell23-Jan-22 7:40
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GeneralRe: necessity to use .Any() to check if an IEnumerable<T> result has no items without iterating over it ? Pin
BillWoodruff25-Jan-22 3:58
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GeneralRe: necessity to use .Any() to check if an IEnumerable<T> result has no items without iterating over it ? Pin
jschell30-Jan-22 6:22
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