c# (Csharp) and .NET :- Difference between IEnumerable and IEnumerator.

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In this c# video video we will try to understand in what scenarios we should use IEnumerable and what scenarios we should use IEnumerator.
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[@dnfvideo]

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[@yaarkhakf]

now i can die in peace

[@phre3k187]

RIP in peace.

[@priyankabiswal8394]

:D

[@jasonmiller1347]

This made me laugh so hard. But its so true. Programming can get so confusing at times

[@MicroftHunter]

LOL :D

[@sabinshrestha8176]

:p

[@ZhuShisubi]

This question has been going around for years and finally someone who just answered it in a very in-depth yet simple way. Thanks from Master Zhu! :)

[@HammadKhanYT]

There is a bug in this code though not obvious in the tutorial. @8:43 In the first function Upto2000, it checks for value weather greater than 200 and then jumps to the second function. But when it jump into the second function o.MoveNext is called and then it print the NEXT value not the current value. So the program is flawed in a sense that the condition check on a value, jump to the second function and then does not uses that value but pull in the next value. It will be more obvious if lets say after 2002, there is a value 1999, it will print in correct value.

[@muslimresearcher6062]

I think the more accurate syntax for the difference between IEnumerable and IEnumerator is that: it is not the IEnumerable or IEnumerator maintains the state or not, but the technique of iteration through IEnumerable or IEnumerator rests the position or not. As you loop through IEnumerable with foreach loop, the foreach loop automatically resets the IEnumerable position to the initial position each time you iterate. While as you iterate through IEnumerator with MoveNext() method the position is maintained with the new iteration loop, because nothing automatically changes the position of IEnumerator and if you want the initial position of IEnumerator you must use Reset() method. So, the technique used to iterate through IEnumerable rests the position automatically each time you iterate, while The technique used to iterate through IEnumerator begins the iteration from the last IEnumerator position and no automatic reset is carried out in IEnumerator iteration.

[@shiftstudiong]

thank you for this concept.

[@rajkumararora7366]

Very well explained in simplistic words. This truely signifies the role of a good teacher. Shiv sir you are the best !!! Keep it up...

[@RajMalhotra-hf3bv]

Explained very good. Only one small correctionwhere you have said IEnumerable instead of IEnumerator. Statement from Video- " IEnumrable remember state while IEnumerable does not"Look at time 12:20 in video

[@kvguitarist]

Great video... Would just like to point out one thing... Maybe no one noticed it but at 12:25, you say "The Biggest difference between IEnumerable and IEnumerator is that IEnumerable REMEMBERS STATES while IEnumerable DOES NOT." I think you wanted to say "IEnumerator remembers states while IEnumerable does not" Obviously that was an accident. But just wanted to point out. Thank you so much for the help!

[@minhaj040182]

Total Out of Context. IEnumerable is only forward loop and commonly used to list any thing without user interfere while IEnumerator is bidirectional that is Forward and Backward and commonly used in paging view so that user can move forward or backward or reset while can not achieve by iEnumerable.

[@dnfvideo]

IEnumerator does not have a back method as such. So its not REALLY Bidirectional

[@kvguitarist]

Also at 10: 16 we should pass int i in the IEnumerable example to 2nd function Iterate2001andAbove() instead of passing o (which is the full list). This will fix listing the years multiple times... :-) Hope that helps.. Thank you once again!

[@MsRohit35]

Was going to comment the same

[@THWUFAILUZAMAN]

we can use foreach with oyears right? then why you convert oyears to IEnumerable explicity?

[@mrityunjoysen10]

Yes right, I too thought the same question. Although I think as the video is 9 years old maybe lists were not directly iterable in that version of C#.

[@ASP4U]

Please try to make video on MVC Layout. which should not refresh entire layout for each request

[@vchandm23]

I want to know who are those two idiots who disliked this video ..... By the way this is amazing ShivPrasad ..... Thanks for sharing this video in youtube ......

[@shishirmathew1999]

Error in 12:25, In place of IEnumerable to IEnumerator remembers its state.

[@yannickkiangoma750]

All before you did not ear it....

[@bhuwanpandey4342]

IEnumerable internally use IEnumerator then why it does not maintain the state

[@bklynmarine91]

I don't seem to get the point, why cast oyears to IEnumerable and still use a for each loop to iterate through when you could have used the list and done the same thing?

[@VArsovski10]

You never had the need to find Nth element in a list ??, or even better - on what position is the element X in a list ?? Funny how I always used a foreach, and then used an outside counter to "update" the current position, in the foreach-loop itself till a certain condition is met :P

[@ildanny74]

The explanation is totally misleading. In the example ienum IS the list. It's the same instance of the original object. On the other hand, ienumerat is a DIFFERENT object, a different class that is used to iterate through the items of the List. Indeed from ienum you can obtain a reference to the initial List through a CAST. Ienumerator cannot. So he's comparing a class with a "utility" for that class. The following code shows better the differences: List e = new List(){1,2,3,4,5}; IEnumerable en = e; var enumerator = e.GetEnumerator(); Console.WriteLine(en.GetType()); //it writes: System.Collections.Generic.List`1[System.Int32] Console.WriteLine(e.GetType()); //it writes: System.Collections.Generic.List`1[System.Int32] Console.WriteLine(enumerator.GetType()); //it writes: System.Collections.Generic.List`1+Enumerator[System.Int32] Console.WriteLine(object.ReferenceEquals(en, e)?"same object":"Not the same object!"); //it writes: same object Console.WriteLine(object.ReferenceEquals(enumerator, e)?"same object":"Not the same object!"); //it writes: Not the same object! The fact that the video doesn't clarify this aspect, makes it completely useless to understand the real differences between the two interfaces.

[@MrJojo1089]

A nice one. am just bit confused why did you need an explicit casting while creating the IEnumerable?The list was anyway of int right???

[@Grygier94]

It's not about int, it's about IEnumerable. Because List implements more interfaces, not only IEnumerable and generally has more features. So when you store the reference of list in IEnumerable you won't have access to all List features, just the features IEnumerable implements. You got to cast it explicitly because you limit it functionality.

[@MerinNakarmi]

By limiting the functionality, does it have any benefit, like in terms of time and memory?

[@LoveShowsNostalgic]

Thanks a lots keep posting for us please 🙏👍 ☺️

[@koschannel4935]

what the hell, of course IEnumerable should not save position of current element, because you're using foreach loop to check all the elements of the collection from START to END, but when u're using IEnumerator u're using method MoveNext, witch saving position of current element and when u're using other method u're still using the same object, so position of current element in this object will be fcking the same. So, what the hell was it?

[@malehakim248]

I still dont understand why and when to use IEnumerable or IEnumerator. I see all you've done can be easily achieved with the List above....Please enlight me on this.

[@anastasialaric1517]

For example you have a program in which you want to loop through some list but you want to restrict the collaborator from accessing methods from the List (Clear, Remove At etc). You will use IEnumerable to achieve this. Basically what collaborator can't do know is Clear list which ensures there will be no unexpected behaviour of the program.

[@PramodSingh-kc1ne]

For example you have a program in which you want to loop through some list but you want to restrict the collaborator from accessing methods from the List (Clear, Remove At etc). You will use IEnumerable to achieve this. Basically what collaborator can't do know is Clear list which ensures there will be no unexpected behaviour of the program.

[@rostfomin]

@@PramodSingh-kc1ne Wtf you copy pasted the same comment from above a year later?

[@sachinambre9451]

List already implement IEnumerable internally, that's the reason we can directly use foreach on List "oyears", then why are we in first place converting it to IEnumerable?

[@josediogo1015]

I dont understand why ienumerable is useful. If i try to use the exact same code shown in the begining, but without Ienum it still works fine. Is it automatically implemented in recent. Net versions? Am i missing something

[@deepakshrestha2672]

when it was 2001 in the first method, then the list is passed to next method and in next method, the current value is 2001 but after while(o.movenext()) the current changes into 2002 so 2001 got kind of skip. right?

[@tuhinmanna1837]

Yes... Got any sol?

[@deepakshrestha2672]

@@tuhinmanna1837 nope sorry

[@AmmarTheTrainer]

at the end we get to know about the main difference between both IEnumerable and IEnumerator . But the question is " why we need all these to implement a loop ?"

[@monochromenight8943]

This helped me understand the reasoning: programmingwithmosh.com/csharp/ienumerable-and-ienumerator/ To be able to use loops, the information needs to be exposed, which violates the OOP guideline of information hiding. Implementing the interfaces makes iteration possible without having to make the class's structure public.

[@pratikgajjar6183]

@@monochromenight8943 that was really helpful, thanks !

[@stbny4444]

why not just use a for loop without having to even bother with the IEnumerable or IEnumerator? This is why I don't understand these two data types.

[@arunntbe]

Really nice video!! you have mentioned that IEnumeratble internally uses IEnumerator, so why it does not remember the current cursor position?

[@sushmabaijv4158]

Thank you very much now I got very clear idea about these two interfaces thanks once again

[@netran104]

we can directly for each over the list. here the example isn’t showing the purpose of using ienumerable i.e. abstraction

[@tobyccw]

why no need to write own content of method like moveNext(), isn't it just empty method from IEnumerator?

[@captainofouterspace]

If the o.Current was 2001 when it got passed to the other method, wouldn't the o.MoveNext in the While loop immediately move to 2002? Hence skipping 2001?

[@captainofouterspace]

I see now. I watched it again. It does skip it but the 2001 gets written before the if > 2000 check.

[@deepakshrestha2672]

yes when it was 2001 in the first method, then the list is passed to next method and in next method, the current value is 2001 but after while(o.movenext()) the current changes into 2002 so 2001 got kind of skip.

[@timsu5412]

The cast is redundant, of course a list will be of type of IEnumerable.

[@SomethingWOW0]

this video explanation was boom boom bummer. Not a short and sweet. I am going to sleep, see you tomorrow .

[@sashidhar2285]

Whats the point of this video? You just showed how it is done and explained one basic difference.

[@avinashsharma5942]

Is there any difference between enumerator and yield coz they both perform stateful iteration

[@pranavb9768]

For this particular topic I find bangar raju's explanation a bit better

[@davidbarth80]

in practice where would you apply the technique to pass the enumator to another function?

[@manchusandy1]

I'm also looking for the same bro. Please respond to this comment in case you found the answer.

[@athiramsubbiah2387]

12:27 Correction: IEnumerator remembers states wheras Ienumerable does not

[@NotMarkKnopfler]

If you had passed i to the second function it would have started from the correct place in the list rather than from the beginning.

[@PVP-learn]

Great explanation ...u reduced my stresssss..

[@AhmadElkhouly]

Thank you. In short, IEnumerable is the collection itself that can be iterated. IEnumerator is an enumerator object that's used to iterate through a collection of data. So for a collection to be enumerable it must provide an enumerator object. IEnumerable exposes the GetEnumerator method that provides that enumerator.

[@rtrs5413]

Please make a video on iqueryable and idisposable because you are best

[@sadaqat4728]

great work man. hardworking and talented people like you deserve subscribers and appreciation rather than those loser tiktokers.

[@0Speedo]

the fking 5 dollar mic jesus...

[@UbergonMX]

wouldn't it be the same if somehow u change the method you do "yield return" on IEnumerable? seeing your "c# Yield keyword". which would be better?

[@jimmynguyen7961]

Love these videos. Very comprehensive explanations.

[@arun020391]

If foreach is the case and we're not interested in current position then why should we choose IEnumerable too instead of we might have use object of List in foreach right and why we go for IEnumerable? can you please anyone clear my doubt, Thank you.

[@viranirav]

Thanks for the video showing the difference between IEnumerable vs IEnumerator. Question, shouldn't we pass int i in the IEnumerable example (when modified at min:11) to 2nd function Iterate2001andAbove instead of passing o (which is the full list). This should fix the results & each year will get listed only once.

[@Sunstriderko]

yes that would fix the problem. Anyways, the goal is to show that there might be some cases where you want to pass a whole collection to the next method and do something with it which is more complex than just writing it into console.

[@MuhammadYousaf-gd5rs]

IEnumerator is built for creating your own data types which can be looped through. Its up to you how you implement it. You have 1 billion items in a file, if you create a IEnumerable data type to get these items you will be out of memory. But if you implement IEnumerator you can get 1 item at a time and only need 1 item memory to store that value. Then you move next and get next item. It will be very fast and instant for your application to load and loop items.

[@tomyang7788]

so would not the year 2001 be printed twice one time by the function iterate19to2001 and iterate2001andAbove

[@thisisnehlem]

Thank your clear explation sir thumbs up from PH🇵🇭

[@kris4117]

Now that I understood what I need to.... I am all set for Nirvana - Guru ji with your blessings.

[@sudhid8765]

Super shiv sir thanks for making my learning easy. I got one doubt to make the ienumerable remember cursor position can we use getenumerator()?

[@dnfvideo]

Its already uploaded. we would like to clarify to everyone here what videos we upload on youtube are a very very small part what we have on questpondvd.

[@Rahul999_Official]

Very well explained the details.

[@gen_jain]

Wow Sir Awesome ! Nicely explained loved it 😊😊

[@pankajjha1914]

thnku sir. it was very helpful.

[@jamesjackson414]

Very good video. As always, well explained, easy to follow code and example. Thanks for sharing with the world.

[@pranavmathur8436]

I believe you should pass i instead of o while describing innumerable lately.

[@khurramsultan2040]

i dont know why some stupid people are disliking these videos. this guy has great way of teaching and he is doing it for free and on the other hand he is very well experienced and sharing his experience

[@kopilkaiser8991]

I had these exact questions and you have answered really well with simple and clear explanation. Thank you!

[@vinaykrishnasharma5024]

Cleared a very important concept. Thanks a lot.

[@amolj9476]

you are master Shi Fu of .Net!

[@Nicetrycutiepie]

Best example I have seen,it's registered in my mind.

[@kacy6014]

Why does this vid have disklikes?

[@ambientsoda106]

Yeah in the newer version of .net core I thought the enumerable uses a numerator it actually creates one for you.

[@lifeinanutshell28]

i love your explanation! thank you so much! you saved me too ... :)

[@Archak77]

Excellent explanation sir ...Thank you 🙏

[@rajasekharjangam4999]

Super explanation bro..

[@ManasTunga]

I think it is completely base lase to compare IEnumerable interface with the IEnumerator interface, and to conclude that the former doesn't remembers the cursor position and later does.

[@mrsoo9687]

i love your explanation! thank you so much! you saved me!

[@paulvincent9473]

Very good explanation

[@lokesh5266]

IEnumerator can maintain the state. But as you said IEnumerable uses IEnumerator internally than my question is why IEnumerable cannot maintain the state. ??

[@OlafChujko]

Enumerable is an interface implemented by a collection allowing you to iterate over it. Enumerator is an interface for an object pointing onto a certain element of a collection with options to: jump to the next element, check if there's an element present and retrieve the element. A collection (implementing the Enumerable interface) doesn't contain information about where the various enumerators are pointing at - and why should it, since it's the enumerators job. It's not entirely correct to say that an Enumerable (object) uses Enumerator internally. A for each loop does use the Enumerator internally, and uses the Enumerable to provide the Enumerator. I hope I didn't manage to make it even more complicated that it was.

[@Bigblue_YT]

Tanks for this show. I learned a lot with video.

[@zeroxcrusher]

I dont get it. Arent lists, arrays and strings already IEnumerable?

[@soniasardana890]

hi, dnfvideo. Can you please give me the link where diff. between GET vs POST is posted on youtube.

[@MansoorAman]

Great video, I think your conclusion may be misleading. It's not that the IEnumerable variable is unable to remember its state, it is that you iterate your IEnumerator variable through the data structure using the MoveNext method so that it points at the next element in each iteration through the for loop. The foreach loop used with the IEnumerable is clever enough to understand what you really want to do when you "loop through an IEnumerable"; because it loops through the data structure that the IEnumerable is currently pointing to, start at its current position.

[@tthamil]

I was very confused between IEnumerable and IEnumerator before the video, I had a very clear explanations from your videos in depth.Thank You.

[@MrShreedar]

12:26 🤔 IEnumarable remembers states. While IEnumarable does not.

[@HirakiSHIKI]

What's the error here, can you explain?

[@MrShreedar]

@@HirakiSHIKI used same word for both. Instead of using IEnumerator.

[@amreshchandra4098]

Oh lastly got it.thanks

[@sarathbaiju6040]

Thank you for this very clear explanation

[@BrunoDemolishment]

Wow, very good! Would you do a video on the ICollection interface, the IList interface and the IDictionary interface? You explaine very well peace

[@rishabh719]

how t o iterate reverse using IENUMERATOR

[@ISHANICUTIEPIE]

Superb explanation

[@maheswarreddy.madithati]

Very good video...........

[@rajendraprasad8814]

The video was awesome...i was finding it difficult to understand the difference from many sites, this video was crisp and clear...kudos

[@jumbo999614]

so ienumerable resets itself to 1st position everytime it is passed to other method as parameter

[@jitendravirkayade3466]

it really help me to understand basic difference, Thanks,

[@parajn]

use for loop with index to find position when using ienurable

[@charlliemurphy8381]

Very good explanation, thank you.

[@thegr8raj1]

Very nice explanation. Thanks for the video.

[@mrk10000]

You always give excellent examples and analogy, thanks a lot for sharing

[@sankar6409]

Great Good! explanations Thank you

[@mahalakshmip9618]

Very good Explanation for Enumerator and Enumerable

[@brynarn]

Love your videos

[@korlakuntanagendrababu2432]

Nice explanation

[@sdss315]

This is nice, I learned it, Thank you sir !

[@treasure2387]

you can pass a reference of an IEnumerator  to the function and you solve the pointer issue

[@HFamilyDad]

now I can sleep

[@zuzuba3481]

Well done. No words to appreciate. Long time confusion is cleared..