• Announcements

    • khawk

      Download the Game Design and Indie Game Marketing Freebook   07/19/17

      GameDev.net and CRC Press have teamed up to bring a free ebook of content curated from top titles published by CRC Press. The freebook, Practices of Game Design & Indie Game Marketing, includes chapters from The Art of Game Design: A Book of Lenses, A Practical Guide to Indie Game Marketing, and An Architectural Approach to Level Design. The GameDev.net FreeBook is relevant to game designers, developers, and those interested in learning more about the challenges in game development. We know game development can be a tough discipline and business, so we picked several chapters from CRC Press titles that we thought would be of interest to you, the GameDev.net audience, in your journey to design, develop, and market your next game. The free ebook is available through CRC Press by clicking here. The Curated Books The Art of Game Design: A Book of Lenses, Second Edition, by Jesse Schell Presents 100+ sets of questions, or different lenses, for viewing a game’s design, encompassing diverse fields such as psychology, architecture, music, film, software engineering, theme park design, mathematics, anthropology, and more. Written by one of the world's top game designers, this book describes the deepest and most fundamental principles of game design, demonstrating how tactics used in board, card, and athletic games also work in video games. It provides practical instruction on creating world-class games that will be played again and again. View it here. A Practical Guide to Indie Game Marketing, by Joel Dreskin Marketing is an essential but too frequently overlooked or minimized component of the release plan for indie games. A Practical Guide to Indie Game Marketing provides you with the tools needed to build visibility and sell your indie games. With special focus on those developers with small budgets and limited staff and resources, this book is packed with tangible recommendations and techniques that you can put to use immediately. As a seasoned professional of the indie game arena, author Joel Dreskin gives you insight into practical, real-world experiences of marketing numerous successful games and also provides stories of the failures. View it here. An Architectural Approach to Level Design This is one of the first books to integrate architectural and spatial design theory with the field of level design. The book presents architectural techniques and theories for level designers to use in their own work. It connects architecture and level design in different ways that address the practical elements of how designers construct space and the experiential elements of how and why humans interact with this space. Throughout the text, readers learn skills for spatial layout, evoking emotion through gamespaces, and creating better levels through architectural theory. View it here. Learn more and download the ebook by clicking here. Did you know? GameDev.net and CRC Press also recently teamed up to bring GDNet+ Members up to a 20% discount on all CRC Press books. Learn more about this and other benefits here.
Sign in to follow this  
Followers 0
Jaap85

Freeing up memory

9 posts in this topic

Hello everybody,

I just created a small test program to see how it would worked after i compiled it. The program was created in Visual Studio using C#. The main thing it does, is adding content from a web page (by reading html source code) to a list.

At some point in the program, i try to remove items from the list (to clear memory usage). However, i run into a problem. I want to remove all items in a list that meet a certain criterium. My code is as follows:

foreach item in list:
> if item.status meets criterium
> list.remove(item)

However, this code doesn't work. The error i get is that i am not allowed to alter the list inside the for loop.

How could i fix this problem? Right now my (very simple) program uses about 2 GB of memory after running for an hour or so.

Thank you very much for your ideas and advice!


PS. if removing items of the list probably won't fix my memory issues i would be happy to hear any other ideas or tips.
1

Share this post


Link to post
Share on other sites
There are 2 different ways to approach this problem and the solution will depend on what your requirements are:

Solution #1 iterate through a cloned list:
[source lang="java"]List<String> list;

List<int> cloneList = new List<int>(list);

foreach item in cloneList:
if(item.status meets criterium)
list.remove(item)[/source]
Solution #2 Store the items to remove in another list:
[source lang="java"]List<String> list;
List<String> removeList;

foreach item in list:
if(item.status meets criteria)
removeList.add(item)

foreach item in removeList:
list.remove(item);[/source]

Solution number one will work if you don't mind using a clone/copy function. Sometimes coping can be expensive though but probably not in your case.
Solution number two does only the minimum amount of memory usage and copying based on the implementation of the add function.
0

Share this post


Link to post
Share on other sites
You could check for your criteria before you add it to the list and filter it out that way.

Another option is while looping through your data list create a second reference list of items to be deleted.
Then delete everything you want to delete outside of your foreach loop.
0

Share this post


Link to post
Share on other sites
In Java, you have to use the Iterator method. Foreach in Java wouldn't let you remove an item while iterating the list.

After a minute of Google-fu, it seems that there's no other way in C# but to iterate the list using the for-loop. It'd be easier for you if you iterate backwards.

Using Nypyren's code :) :
[CODE]
for (int i=list.Count-1; i >= 0; --i) {
if (list[i] meets criteria) {
list.RemoveAt(i);
}
}[/CODE] Edited by alnite
0

Share this post


Link to post
Share on other sites
To make a guess, close the web connection, then try removing from the list. There's no reason why System.Collections.List or System.Collections.Generic.List<T> themselves should stop you from removing items (aside from out-of-bounds, not-found errors and the like).
0

Share this post


Link to post
Share on other sites
Yeah, you can't remove items from a list while iterating over it with an iterator. You can however do this:

[source lang="csharp"]for (int i=list.length-1; i>=0; i--)
{
var item = list[i];
if (item.condition)
list.RemoveAt(i);
}
[/source]
0

Share this post


Link to post
Share on other sites
[quote name='jefferytitan' timestamp='1349000156' post='4985306']
Yeah, you can't remove items from a list while iterating over it with an iterator. You can however do this:

[source lang="csharp"]for (int i=list.length-1; i>=0; i--)
{
var item = list[i];
if (item.condition)
list.RemoveAt(i);
}
[/source]
[/quote]
*Slaps forehead* Probably shouldn't have posted in the very early AM.
0

Share this post


Link to post
Share on other sites
Sorry for my slow response (have been a bit busy with things other than programming the past few days) but i tried it out and it works! Where my program used to use up to 2GB, it now uses only 40 MB of processor power. Much better!

Thank you very much for your responses.
0

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now
Sign in to follow this  
Followers 0