What is the difference between List of string and ArrayList.

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What is the difference between List<string> and ArrayList. Is there any performance issue?

Posted 29-Jun-11 1:38am

ham_gr80

Updated 29-Jun-11 1:40am

v3

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5 solutions

Solution 2

The difference is that you perform boxing/unboxing (casting the string to object and vice verca) with ArrayList, and generic List<string> allows you to avoid it. Performance of generic classes is better.

And that's what Google came up with.[^]

Posted 29-Jun-11 1:43am

Dima Popov

Updated 29-Jun-11 1:52am

v2

Comments

Tarun.K.S 29-Jun-11 7:58am

хороший ответ! 5!

Sergey Alexandrovich Kryukov 29-Jun-11 12:19pm

Wrong! See my comment.
--SA

Tarun.K.S 29-Jun-11 12:59pm

Aah yes even I realised the mistake after I saw Abhinav's comment. It was due to lack of coffee! LOL!

Tarun.K.S 29-Jun-11 13:02pm

A little off-topic, what is the meaning of your first name? Like meaning of my first name Tarun is "younger"(indeed I do look young!) :)

Dima Popov 29-Jun-11 15:27pm

Dima is short variant of Dmitry, which is a slightly modified Greek name. So it doesn't seem to have any meaning in Russian, though initially had one. There's an article on Wikipedia: http://en.wikipedia.org/wiki/Dmitry. What I can tell you is that it's a very common name. Russian names that do have decent meaning are quite rare.

Sergey Alexandrovich Kryukov 29-Jun-11 17:47pm

Dima,

This is not quite true (I put more info on your name below, I mentioned the meaning). Russian names are mostly biblical or derived from the name of saints, of ancient Jewish or Greek origin. Their decent meanings are pretty well known by linguists, but Russians tends to lack this knowledge. Slavic name, in contrast, are quite well understood. Many Slavic names are quite popular, but there are very few of such names.

Most popular three Russian female names: Vera, Nadezhda, Liubov -- meaning Believe Hope and Love (!). Another popular is Svetlana (Svet translated as Light).

There are even less Russian popular male names of Slavic origin: Sviatoslav and Vecheslav ("Saint Glory" and "Very Glory", something like that). Many think that the popular name Vladimir is Slavic (sounds like "Rule the World"), but I've read linguist say it is of Germanic origin, from Waldemar; Russians just re-interpreted it.

--SA

Dima Popov 30-Jun-11 1:29am

Vera, Nadezhda, Liubov - I didn't think of those names. That's because they became unpopular in the 70s, I suppose.

Sergey Alexandrovich Kryukov 2-Jul-11 22:53pm

Not really. They were relatively popular all of the time, never on the top perhaps. I don't remember any shift in 70th.
--SA

Tarun.K.S 30-Jun-11 3:45am

I see, I got so much info here. I have heard of Svetlana, she is a tennis star. http://en.wikipedia.org/wiki/Svetlana_Kuznetsova.

Tarun.K.S 30-Jun-11 3:42am

Aah I see, thanks for the info. So as SA says, most names are derived from saints and gods. Dmitry is very common in Russia I guess, including Vladmir too! Speaking of Vladmir, it reminds of Putin, so whom do you want to see as the next president, Putin? I have a special respect for Putin. Sorry for my poor understanding about your constitution.

Dima Popov 30-Jun-11 5:07am

Yes, the president Medvedev's first name is Dmitry too. Speaking of who will be the next president of Russia, I think it will be Putin (not that I want it). Russian politics are actually very predictable. There's only Putin and his people. Back in 2008 he let Medvedev to be in charge for 4 years as he understood that changing the constitution would not be appreciated in the West. So he saved the image of democratic country, but now it'll be his turn again, 6 years now, due to the change of constitution which came almost unnoticed.
It is so clear, who is Batman and who is Robin (a comparison that came from Wikileaks).

Tarun.K.S 30-Jun-11 6:24am

Hmm I got your point, he is a very clever guy. So if Putin is elected, he will remain as President for a whopping 6 years!!! Oh boy! Man I think very few people will be happy to see this. Are you happy with this development? Why I admire Putin is that he handled the United States pretty well regarding the placing of Missiles in Poland and the Ossentia War. He is also a good friend of India. Considering the recent polls here: http://en.wikipedia.org/wiki/Russian_presidential_election,_2012, only 27% support Putin. BTW whom do you want to see as the next president?

Dima Popov 30-Jun-11 7:59am

It's hard to say whom I see as the next president as the opposition is weak and its image is distorted through media. The 'choice' is Putin or Medvedev? That's funny.
The last elections that had some meaning took place in '96. The choice was democrat Eltsin or communist Zyuganov. Eltsin was oligarchs' candidate, and thus had the media support and won. After that, the result was known long before the elections. Actually I had a bet in 2006, which I won two years later, when Medvedev was elected. It's as easy as that: you turn on TV and the man that is shown on all the channels is the next president.
I really think that we need a change, and we need to take the European direction, free elections and multi-party system, you know. Now it seems impossible though.

Tarun.K.S 30-Jun-11 9:10am

Lol you won the bet! But Russia is a multi-party democracy(source-Wikipedia) or is the ground-reality different? I think I got your point, the media is kind of state-controlled, not much press-freedom is there, that's sad. :( The hard truth is you don't have any choice on whom to elect. You are right, your country needs a revolution, a change, you all need more rights. But that's hard too, as media plays an important role. Here in India, a small revolution is slowly gaining pace, against the corrupt govt officials. There is so much black money stuffed in Swiss banks that if we get it back, we will become the richest country after US. We are protesting and slowly bringing the current govt down to its knees.
I would like to see a similar protest in your country too.

Dima Popov 30-Jun-11 10:08am

I would also like to see more protest activity, but not a revolution, certainly. The government should let loose the opposition, so that there would be legit ways to influence the politic situation. They seem to be creating a fictitious opposition party instead.

Tarun.K.S 1-Jul-11 3:16am

Hmmm right. Man I have a lot of questions to ask, seems enough for now! :P
It was really great talking to you. Thanks a ton for taking your time out enhancing my knowledge about Russia, I certainly learned many things. I will disturb you again some time later as you rarely come to CodeProject. :P
Имейте большой день :)

Dima Popov 1-Jul-11 3:42am

You're welcome :)

Sergey Alexandrovich Kryukov 2-Jul-11 22:57pm

Just a short note. Calling Eltsin a "democrat" and Zyuganov a "communist" is both pretty ridiculous :-)
--SA

Dima Popov 3-Jul-11 4:37am

That's what they called themselves :)

Sergey Alexandrovich Kryukov 3-Jul-11 4:41am

That's more accurate :-)
--SA

Dima Popov 29-Jun-11 8:14am

Thanks :)

Sergey Alexandrovich Kryukov 29-Jun-11 12:20pm

String is "always boxed" anyway. As boxing/unboxing does not takes place for this type, there is no performance leak.
But if the user does "string myString = myObject as string", it will eat up time.

--SA

Dima Popov 29-Jun-11 12:40pm

I realized that when reading Abhinav's answer. Still thanks, I really appreciate your comments.

Tarun.K.S 29-Jun-11 13:03pm

A little off-topic, may I know the meaning of Dima? In my case, Tarun means "younger". Just curious!

Sergey Alexandrovich Kryukov 29-Jun-11 17:32pm

Dima is the Russian "standard" "pet" (diminutive) form of the name Dmitriy (Russian: Дмитрий) of Greek origin (also Dimitriy). The meaning is "devoted to", "dedicated to", see http://en.wikipedia.org/wiki/Dmitry.

--SA

Dima Popov 30-Jun-11 1:29am

Devoted to goddess Demetra :) I knew that

Tarun.K.S 30-Jun-11 3:49am

Thanks for the info! I think I got the meaning of your first name too : http://en.wikipedia.org/wiki/Serge_%28first_name%29. I would also like to know whom would you like to see the next president of Russia? Putin again?

Sergey Alexandrovich Kryukov 29-Jun-11 17:33pm

Dima, did you know that?
--SA

Solution 1

A generic List is more efficient because it deals with just the specified object type. An ArrayList requires boxing because it supports multiple types in a single list. It's almost always better to use a List rather than an ArrayList.

Posted 29-Jun-11 1:42am

#realJSOP

Comments

Tarun.K.S 29-Jun-11 7:58am

Right.

Sergey Alexandrovich Kryukov 29-Jun-11 12:19pm

Sorry, not exactly so. String is "always boxed" anyway. As boxing/unboxing does not takes place for this type, there is no performance leak. But if the user does "string myString = myObject as string", it will eat up time.
--SA

Solution 3

http://collecteddotnet.wordpress.com/2009/08/11/basic-difference-between-arraylist-and-list/[^]

Posted 29-Jun-11 1:44am

Mohd Wasif

Solution 5

ArrayLists are essentially deprecated as they're untyped - you need to use casts with them - and they're slower and less space efficient for value types because they require the items to be boxed.

Generic lists were introduced with .Net 2.0 and are the way to go. Often a List is better than an array, with few downsides.

Posted 29-Jun-11 3:13am

Ramalinga Koushik

Comments

Sergey Alexandrovich Kryukov 29-Jun-11 12:23pm

Not using ArrayList is a good point. Indeed, it should ***never*** be used.

As to space and speed -- not quite so. More exactly -- it depends. It depends on the type of the element (if boxing/unboxing needed) and on how the user does the case. Please see my comments to other answers.
--SA

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Abhinav S · Accepted Answer · 2011-06-29T01:46:00

Solution 4

Not much I would think - since there is no boxing / unboxing here.
Implementing List<t> might just still come out better in terms of performance because there is no need to do any type checking at runtime.

Two more interesting reads on this topic -
http://blogs.msdn.com/b/joshwil/archive/2004/04/13/112598.aspx[^]
http://blog.drorhelper.com/2008/10/why-should-i-use-list-and-not-arraylist.html[^]

Posted 29-Jun-11 1:46am

Abhinav S

Comments

Tarun.K.S 29-Jun-11 8:00am

How come there is no boxing/unboxing in ArrayList?

Abhinav S 29-Jun-11 8:13am

The OP has compared List<string> with ArrayList. Since a string is already on the heap, there will be no boxing.
If the user was talking about comparing List<int> with an ArrayList there would be more performance benefit.

Tarun.K.S 29-Jun-11 8:27am

Aah right, OP is comparing List<String> and ArrayList. Uff, let me get myself a cup of coffee!

Abhinav S 29-Jun-11 9:21am

:)

#realJSOP 29-Jun-11 8:40am

Generally speaking, though, he should avoid using an ArrayList whenever possible. It's simply not necessary in about 99.999% of all cases.

Abhinav S 29-Jun-11 9:19am

Agreed.

Sergey Alexandrovich Kryukov 29-Jun-11 12:21pm

You are right, my 5, but it depends on how the user casts to string.
Please see my comment to (not quite correct) answer by John.
--SA

Abhinav S 29-Jun-11 13:51pm

Thank you. I myself was confused after posting my own answer but reading what the others posted. So your advice is very useful. Hopefully it will help everyone (including me) understand a little bit about List<t> and performance.

What is the difference between List of string and ArrayList.

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What is the difference between List of string and ArrayList.

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