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  • Item in multiple lists

    - by Evan Teran
    So I have some legacy code which I would love to use more modern techniques. But I fear that given the way that things are designed, it is a non-option. The core issue is that often a node is in more than one list at a time. Something like this: struct T { T *next_1; T *prev_1; T *next_2; T *prev_2; int value; }; this allows the core have a single object of type T be allocated and inserted into 2 doubly linked lists, nice and efficient. Obviously I could just have 2 std::list<T*>'s and just insert the object into both...but there is one thing which would be way less efficient...removal. Often the code needs to "destroy" an object of type T and this includes removing the element from all lists. This is nice because given a T* the code can remove that object from all lists it exists in. With something like a std::list I would need to search for the object to get an iterator, then remove that (I can't just pass around an iterator because it is in several lists). Is there a nice c++-ish solution to this, or is the manually rolled way the best way? I have a feeling the manually rolled way is the answer, but I figured I'd ask.

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  • Doubly Linked Lists Implementation

    - by user552127
    Hi All, I have looked at most threads here about Doubly linked lists but still unclear about the following. I am practicing the Goodrich and Tamassia book in Java. About doubly linked lists, please correct me if I am wrong, it is different from a singly linked list in that a node could be inserted anywhere, not just after the head or after the tail using both the next and prev nodes available, while in singly linked lists, this insertion anywhere in the list is not possible ? If one wants to insert a node in a doubly linked list, then the default argument should be either the node after the to-be inserted node or node before the to-be inserted node ? But if this is so, then I don't understand how to pass the node before or after. Should we be displaying all nodes that were inserted till now and ask the user to select the node before or after which some new node is to be inserted ? My doubt is how to pass this default node. Because I assume that will require the next and prev nodes of these nodes as well. For e.g, Head<-A<-B<-C<-D<-E<-tail If Z is the new node to be inserted after say D, then how should node D be passed ? I am confused with this though it seems pretty simple to most. But pl do explain. Thanks, Sanjay

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  • How can I write simulations in Erlang?

    - by rick
    Hi guys, I want to do some numerical stuff in Erlang like this: You've got an array with the following values: [2,3,4] In each iteration, you calculate 0.1 * [n-1] + 0.7 *[n] + 0.2 * [n+1] This becomes the new [n]. If n == 0 then [n-1] = 0. If [n] == length of array then [n] = 0. So I try an example: [2,3,4] calculations: 0.1 * 0 + 0.7 * 2 + 0.2 * 3 = 2 0.1 * 2 + 0.7 * 3 + 0.2 * 4 = 3.1 0.1 * 3 + 0.7 * 4 + 0.2 * 0 = 3.1 So [2,3,4] becomes to [2, 3.1, 3.1] after one iteration. I know how to write this in a non-functional language like C. But I have difficulties to imagine, how this could be done in Erlang. I found some tutorials on how you read a file to a list. So this is not the problem. How can I spawn different Erlang processes that each process has one element of the list? How can I do calculations by communicating with 'the neighbors', so that the neighbors know where their neigbors are generically, without specifying each? How can I collect the data into a list? Eventually, is it possible to solve that problem in Erlang at all? Thanks for your help.

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  • Double Linked List header node keeps returning first value as 0

    - by Craig
    I will preface to say that this is my first question. I am currently getting my Masters degree in Information Security and I had to take C++ programming this semester. So this is homework related. I am not looking for you to answer my homework but I am running into a peculiar situation. I have created the program to work with a doubly linked list and everything works fine. However when I have the user create a list of values the first node keeps returning 0. I have tried finding some reading on this and I cannot locate any reference to it. My question is then is the header node(first node) always going to be zero? Or am I doing something wrong. case: 'C': cout<<"Please enter a list:"<<endl; while(n!=-999){ myList.insert(n); cin>> n;} break; I now enter: 12321, 1234,64564,346346. The results in 0, 12321, 1234, 64564,346346. Is this what should happen or am I doing something wrong? Also as this is my first post please feel free to criticize or teach me how to color code the keywords. Anyway this is a homework assignment so I am only looking for guidance and constructive criticism. Thank you all in advance So I cannot figure out the comment sections on this forum so I will edit the original post The first section is the constructor code: template <class Type> doublyLinkedList<Type>::doublyLinkedList() { first= NULL; last = NULL; count = 0; } Then there is my insert function : template <class Type> void doublyLinkedList<Type>::insert(const Type& insertItem) { nodeType<Type> *current; //pointer to traverse the list nodeType<Type> *trailCurrent; //pointer just before current nodeType<Type> *newNode; //pointer to create a node bool found; newNode = new nodeType<Type>; //create the node newNode->info = insertItem; //store the new item in the node newNode->next = NULL; newNode->back = NULL; if(first == NULL) //if the list is empty, newNode is //the only node { first = newNode; last = newNode; count++; } else { found = false; current = first; while (current != NULL && !found) //search the list if (current->info >= insertItem) found = true; else { trailCurrent = current; current = current->next; } if (current == first) //insert newNode before first { first->back = newNode; newNode->next = first; first = newNode; count++; } else { //insert newNode between trailCurrent and current if (current != NULL) { trailCurrent->next = newNode; newNode->back = trailCurrent; newNode->next = current; current->back = newNode; } else { trailCurrent->next = newNode; newNode->back = trailCurrent; last = newNode; } count++; }//end else }//end else }//end Then I have an initialization function too: template <class Type> void doublyLinkedList<Type>::initializeList() { destroy(); } Did I miss anything?

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  • c# Find value in a range using lambda

    - by n4rzul
    I'm trying to find an item in a list of values based on another value using a lambda expression using the Find method. In this example I'm expecting to get back -1000, but for the life of me, I just can't come up with the proper lamda expression. If that sounds confusing I hope the code and comments below explain it better. TIA. using System; using System.Collections.Generic; namespace TestingStuff { class Program { static void Main(string[] args) { double amount = -200; //The Range of values List<MyValue> values = new List<MyValue>(); values.Add(new MyValue(-1000)); values.Add(new MyValue(-100)); values.Add(new MyValue(-10)); values.Add(new MyValue(0)); values.Add(new MyValue(100)); values.Add(new MyValue(1000)); //Find it!!! MyValue fVal = values.Find(x => (x.Value > amount) && (x.Value < amount)); //Expecting -1000 as a result here since -200 falls between -1000 and -100 //if it were -90 I'd expect -100 since it falls between -100 and 0 if (fVal != null) Console.WriteLine(fVal.Value); Console.ReadKey(); } } public class MyValue { public double Value { get; set; } public MyValue(double value) { Value = value; } } }

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  • String generator issue

    - by Andrey
    I want to write a method which returns a string. So far so good. The creation of the string however is quite complicated. I have 3 string lists - the first one has 155 entries, the second one - 9, the third one 21. I want my method if called enough times(155*9*21) to return all the possible combinations of values from the 3 lists (basically this method should keep count on how many times it was called and return only one combination each time). Any ideas how to accomplish that? I have 155*9*22 possible combinations. The first time the method is called it should take List1(0), List2(0), List3(0). After that in the next 21 iterations, the index of the third list is only changed. Once all the elements from the third list have been used increment the index of the second list and so on. Once the method has produced all the possible combinations (155*9*22) I want it to start from the beginning.

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  • Distinctly LINQ &ndash; Getting a Distinct List of Objects

    - by David Totzke
    Let’s say that you have a list of objects that contains duplicate items and you want to extract a subset of distinct items.  This is pretty straight forward in the trivial case where the duplicate objects are considered the same such as in the following example: List<int> ages = new List<int> { 21, 46, 46, 55, 17, 21, 55, 55 }; IEnumerable<int> distinctAges = ages.Distinct(); Console.WriteLine("Distinct ages:"); foreach (int age in distinctAges) { Console.WriteLine(age); } /* This code produces the following output: Distinct ages: 21 46 55 17 */ What if you are working with reference types instead?  Imagine a list of search results where items in the results, while unique in and of themselves, also point to a parent.  We’d like to be able to select a bunch of items in the list but then see only a distinct list of parents.  Distinct isn’t going to help us much on its own as all of the items are distinct already.  Perhaps we can create a class with just the information we are interested in like the Id and Name of the parents.  public class SelectedItem { public int ItemID { get; set; } public string DisplayName { get; set; } } We can then use LINQ to populate a list containing objects with just the information we are interested in and then get rid of the duplicates. IEnumerable<SelectedItem> list = (from item in ResultView.SelectedRows.OfType<Contract.ReceiptSelectResults>() select new SelectedItem { ItemID = item.ParentId, DisplayName = item.ParentName }) .Distinct(); Most of you will have guessed that this didn’t work.  Even though some of our objects are now duplicates, because we are working with reference types, it doesn’t matter that their properties are the same, they’re still considered unique.  What we need is a way to define equality for the Distinct() extension method. IEqualityComparer<T> Looking at the Distinct method we see that there is an overload that accepts an IEqualityComparer<T>.  We can simply create a class that implements this interface and that allows us to define equality for our SelectedItem class. public class SelectedItemComparer : IEqualityComparer<SelectedItem> { public new bool Equals(SelectedItem abc, SelectedItem def) { return abc.ItemID == def.ItemID && abc.DisplayName == def.DisplayName; } public int GetHashCode(SelectedItem obj) { string code = obj.DisplayName + obj.ItemID.ToString(); return code.GetHashCode(); } } In the Equals method we simply do whatever comparisons are necessary to determine equality and then return true or false.  Take note of the implementation of the GetHashCode method.  GetHashCode must return the same value for two different objects if our Equals method says they are equal.  Get this wrong and your comparer won’t work .  Even though the Equals method returns true, mismatched hash codes will cause the comparison to fail.  For our example, we simply build a string from the properties of the object and then call GetHashCode() on that. Now all we have to do is pass an instance of our IEqualitlyComarer<T> to Distinct and all will be well: IEnumerable<SelectedItem> list =     (from item in ResultView.SelectedRows.OfType<Contract.ReceiptSelectResults>()         select new SelectedItem { ItemID = item.dahfkp, DisplayName = item.document_code })                         .Distinct(new SelectedItemComparer());   Enjoy. Dave Just because I can… Technorati Tags: LINQ,C#

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  • NSFetchedResultsController fetch request - updating predicate and UITableView

    - by Macatomy
    In my iPhone Core Data app I have it configured in a master-detail view setup. The master view is a UITableView that lists objects of the List entity. The List entity has a to-many relationship with the Task entity (called "tasks"), and the Task entity has an inverse to-one relationship with List called "list". When a List object is selected in the master view, I want the detail view (another UITableView) to list the Task objects that correspond to that List object. What I've done so far is this: In the detail view controller I've declared a property for a List object: @property (nonatomic, retain) List *list; Then in the master view controller I use this table view delegate method to set the list property of the detail view controller when a list is selected: - (void)tableView:(UITableView *)aTableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath { NSManagedObject *selectedObject = [[self fetchedResultsController] objectAtIndexPath:indexPath]; detailViewController.list = (List*)selectedObject; } Then, I've overriden the setter for the list property in the detail view controller like this: - (void)setList:(List*)newList { if (list != newList) { [list release]; list = [newList retain]; NSPredicate *newPredicate = [NSPredicate predicateWithFormat:@"(list == %@)", list]; [NSFetchedResultsController deleteCacheWithName:@"Root"]; [[[self fetchedResultsController] fetchRequest] setPredicate:newPredicate]; NSError *error = nil; if (![[self fetchedResultsController] performFetch:&error]) { NSLog(@"Unresolved error %@, %@", error, [error userInfo]); abort(); } } } What I'm doing here is setting a predicate on the fetched results to filter out the objects so that I only get the ones that belong to the selected List object. The fetchedResultsController getter for the detail view controller looks like this: - (NSFetchedResultsController *)fetchedResultsController { if (fetchedResultsController == nil) { NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init]; NSEntityDescription *entity = [NSEntityDescription entityForName:@"Task" inManagedObjectContext:managedObjectContext]; [fetchRequest setEntity:entity]; NSPredicate *predicate = [NSPredicate predicateWithFormat:@"FALSEPREDICATE"]; [fetchRequest setPredicate:predicate]; NSSortDescriptor *sortDescriptor = [[NSSortDescriptor alloc] initWithKey:@"name" ascending:YES]; NSArray *sortDescriptors = [[NSArray alloc] initWithObjects:sortDescriptor, nil]; [fetchRequest setSortDescriptors:sortDescriptors]; NSFetchedResultsController *aFetchedResultsController = [[NSFetchedResultsController alloc] initWithFetchRequest:fetchRequest managedObjectContext:managedObjectContext sectionNameKeyPath:nil cacheName:@"Root"]; aFetchedResultsController.delegate = self; self.fetchedResultsController = aFetchedResultsController; [aFetchedResultsController release]; [fetchRequest release]; [sortDescriptor release]; [sortDescriptors release]; } return fetchedResultsController; } Its almost unchanged from the default in the Core Data project template, the change I made is to add a predicate that always returns false, the reason being that when there is no List selected I don't want any items to be displayed in the detail view (if a list is selected the predicate is changed in the setter for the list property). However, when I select a list item, nothing really happens. Nothing in the table view changes, it stays empty. I'm sure my logic is flawed in several places, advice is appreciated Thanks

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  • Linq to List and IEnumerable issues

    - by Otaku
    I am querying an HTML file with Linq. It looks something like this: <html> <body> <div class="Players"> <div class="role">Goalies</div> <div class="name">John Smith</div> <div class="name">Shawn Xie</div> <div class="role">Right Wings</div> <div class="name">Jack Davis</div> <div class="name">Carl Yuns</div> <div class="name">Wayne Gortonia</div> <div class="role">Centers</div> <div class="name">Lutz Gaspy</div> <div class="name">John Jacobs</div> </div </html> </body> What I'm trying to do is create a list of these folks like in a list of a structure called Players: Structure Players Public Name As String Public Position As String End Structure But I've quickly found out I don't really know what I'm doing when it comes to Linq. I've got this far my my queries: Dim goalieList = From d In player.Elements _ Where d.Value = "Goalies" _ Select From g In d.ElementsAfterSelf _ Take While (g.@class <> "role") _ Select New Players With {.Position = "Goalie", _ .Name = g.Value} Dim centersList = From d In player.Elements _ Where d.Value = "Centers" _ Select From g In d.ElementsAfterSelf _ Take While (g.@class <> "role") _ Select New Players With {.Position = "Centers", _ .Name = g.Value} Which gets me down to the the players by position, but then I can't do much with this afterwards the result type is System.Collections.Generic.IEnumerable(Of System.Collections.Generic.IEnumerable(Of Player)) What I want to do is add these two results to a new list, like: Dim playersList As List(Of Players) = Nothing playersList.AddRange(centersList) playersList.AddRange(goalieList) So that I can then query the list and use it. But it kicks the error: Unable to cast object of type 'WhereSelectEnumerableIterator2[System.Xml.Linq.XElement,System.Collections.Generic.IEnumerable1[Players]]' to type 'System.Collections.Generic.IEnumerable`1[Players]' As you can see, I may really have no idea how to work with all these objects/classes. Does anyone have any insight on what I may be doing wrong and how I can resolve it? RESOLVED: The Linq query needs to return a single iEnumerable, like this: Dim goalieList = From l In _ (From d In players.Elements _ Where d.Value = "Goalies" _ Select d.ElementsAfterSelf.TakeWhile(Function(f) f.@class <> "role")) _ Select New Players With {.Position = "Goalie", .Name = l.Value} and then use goalieList.ToList

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  • C# XMLSerializer fails with List<T>

    - by Redshirt
    Help... I'm using a singleton class to save all my settings info. It's first utilized by calling Settings.ValidateSettings(@"C:\MyApp") The problem I'm having is that 'List Contacts' is causing the xmlserializer to fail to write the settings file, or to load said settings. If I comment out the List then I have no problems saving/loading the xml file. What am I doing wrong... Thanks in advance // The actual settings to save public class MyAppSettings { public bool FirstLoad { get; set; } public string VehicleFolderName { get; set; } public string ContactFolderName { get; set; } public List<ContactInfo> Contacts { get { if (contacts == null) contacts = new List<ContactInfo>(); return contacts; } set { contacts = value; } } private List<ContactInfo> contacts; } // The class in which the settings are manipulated public static class Settings { public static string SettingPath; private static MyAppSettings instance; public static MyAppSettings Instance { get { if (instance == null) instance = new MyAppSettings(); return instance; } set { instance = value; } } public static void InitializeSettings(string path) { SettingPath = Path.GetFullPath(path + "\\MyApp.xml"); if (File.Exists(SettingPath)) { LoadSettings(); } else { Instance.FirstLoad = true; Instance.VehicleFolderName = "Cars"; Instance.ContactFolderName = "Contacts"; SaveSettingsFile(); } } // load the settings from the xml file private static void LoadSettings() { XmlSerializer ser = new XmlSerializer(typeof(MyAppSettings)); TextReader reader = new StreamReader(SettingPath); Instance = (MyAppSettings)ser.Deserialize(reader); reader.Close(); } // Save the settings to the xml file public static void SaveSettingsFile() { XmlSerializer ser = new XmlSerializer(typeof(MyAppSettings)); TextWriter writer = new StreamWriter(SettingPath); ser.Serialize(writer, Settings.Instance); writer.Close(); } public static bool ValidateSettings(string initialFolder) { try { Settings.InitializeSettings(initialFolder); } catch (Exception e) { return false; } // Do some validation logic here return true; } } // A utility class to contain each contact detail public class ContactInfo { public string ContactID; public string Name; public string PhoneNumber; public string Details; public bool Active; public int SortOrder; } }

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  • not able to get a processed list in jquery variable

    - by Pradyut Bhattacharya
    I have html list <ol id="newlist"> <li>Test <ol> <li>1</li> <li>2</li> <li>3</li> </ol> </li> <li>Another test <ol> <li>1</li> </ol> </li> <li>Cool Test <ol> <li>1</li> <li>2</li> </ol> </li> </ol> Now i have hidden the list using the css... #newlist li { display:none; list-style: none; } I want to display the list and the only the descendants which have greater than 1 descendants... the output should be... Test 1 2 3 Another test Cool Test 1 2 I have used jquery and able to get the output... the code i used... $("ol#newlist > li").show(); for (var i = 0; i < $("ol#newlist > li").length; i++) { if ($("ol#newlist > li:eq(" + i + ") ol > li").length > 1) $("ol#newlist > li:eq(" + i + ") ol > li").show(); } the sample page here Now i want all the list in a single variable like i can get the lis in a variable... var $li = $("ol#newlist > li"); but the code $li.add($("ol#newlist > li:eq(" + i + ") ol > li")); is not working... the sample page here Please help... Thanks Pradyut India

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  • building list of child objects inside main object

    - by Asdfg
    I have two tables like this: Category: Id Name ------------------ 1 Cat1 2 Cat2 Feature: Id Name CategoryId -------------------------------- 1 F1 1 2 F2 1 3 F3 2 4 F4 2 5 F5 2 In my .Net classes, i have two POCO classes like this: public class Category { public int Id {get;set;} public int Name {get;set;} public IList<Feature> Features {get;set;} } public class Feature { public int Id {get;set;} public int CategoryId {get;set;} public int Name {get;set;} } I am using a stored proc that returns me a result set by joining these 2 tables. This is how my Stored Proc returns the result set. SELECT c.CategoryId, c.Name Category, f.FeatureId, f.Name Feature FROM Category c INNER JOIN Feature f ON c.CategoryId = f.CategoryId ORDER BY c.Name --Resultset produced by the above query CategoryId CategoryName FeatureId FeatureName --------------------------------------------------- 1 Cat1 1 F1 1 Cat1 2 F2 2 Cat2 3 F3 2 Cat2 4 F4 2 Cat2 5 F5 Now if i want to build the list of categories in my .Net code, i have to loop thru the result set and add features unless the category changes. This is how my .Net code looks like that builds Categories and Features. List<Category> categories = new List<Category>(); Int32 lastCategoryId = 0; Category c = new Category(); using (SqlDataReader reader = cmd.ExecuteReader()) { while (reader.Read()) { //Check if the categoryid is same as previous one. //If Not, add new category. //If Yes, dont add the category. if (lastCategoryId != Convert.ToInt32(reader["CategoryId"])) { c = new Category { Id = Convert.ToInt32(reader["CategoryId"]), Name = reader["CategoryName"].ToString() }; c.Features = new List<Feature>(); categories.Add(c); } lastCategoryId = Convert.ToInt32(reader["CategoryId"]); //Add Feature c.Features.Add(new Feature { Name = reader["FeatureName"].ToString(), Id = Convert.ToInt32(reader["FeatureId"]) }); } return categories; } I was wondering if there is a better way to do build the list of Categories?

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  • Sorting a list of numbers with modified cost

    - by David
    First, this was one of the four problems we had to solve in a project last year and I couldn’t find a suitable algorithm so we handle in a brute force solution. Problem: The numbers are in a list that is not sorted and supports only one type of operation. The operation is defined as follows: Given a position i and a position j the operation moves the number at position i to position j without altering the relative order of the other numbers. If i j, the positions of the numbers between positions j and i - 1 increment by 1, otherwise if i < j the positions of the numbers between positions i+1 and j decreases by 1. This operation requires i steps to find a number to move and j steps to locate the position to which you want to move it. Then the number of steps required to move a number of position i to position j is i+j. We need to design an algorithm that given a list of numbers, determine the optimal (in terms of cost) sequence of moves to rearrange the sequence. Attempts: Part of our investigation was around NP-Completeness, we make it a decision problem and try to find a suitable transformation to any of the problems listed in Garey and Johnson’s book: Computers and Intractability with no results. There is also no direct reference (from our point of view) to this kind of variation in Donald E. Knuth’s book: The art of Computer Programing Vol. 3 Sorting and Searching. We also analyzed algorithms to sort linked lists but none of them gives a good idea to find de optimal sequence of movements. Note that the idea is not to find an algorithm that orders the sequence, but one to tell me the optimal sequence of movements in terms of cost that organizes the sequence, you can make a copy and sort it to analyze the final position of the elements if you want, in fact we may assume that the list contains the numbers from 1 to n, so we know where we want to put each number, we are just concerned with minimizing the total cost of the steps. We tested several greedy approaches but all of them failed, divide and conquer sorting algorithms can’t be used because they swap with no cost portions of the list and our dynamic programing approaches had to consider many cases. The brute force recursive algorithm takes all the possible combinations of movements from i to j and then again all the possible moments of the rest of the element’s, at the end it returns the sequence with less total cost that sorted the list, as you can imagine the cost of this algorithm is brutal and makes it impracticable for more than 8 elements. Our observations: n movements is not necessarily cheaper than n+1 movements (unlike swaps in arrays that are O(1)). There are basically two ways of moving one element from position i to j: one is to move it directly and the other is to move other elements around i in a way that it reaches the position j. At most you make n-1 movements (the untouched element reaches its position alone). If it is the optimal sequence of movements then you didn’t move the same element twice.

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  • Can I use accepts_nested_attributes_for with checkboxes in a _form to select potential 'links' from a list

    - by Ryan
    In Rails 3: I have the following models: class System has_many :input_modes # name of the table with the join in it has_many :imodes, :through => :input_modes, :source => 'mode', :class_name => "Mode" has_many :output_modes has_many :omodes, :through => :output_modes, :source => 'mode', :class_name => 'Mode' end class InputMode # OutputMode is identical belongs_to :mode belongs_to :system end class Mode ... fields, i.e. name ... end That works nicely and I can assign lists of Modes to imodes and omodes as intended. What I'd like to do is use accepts_nested_attributes_for or some other such magic in the System model and build a view with a set of checkboxes. The set of valid Modes for a given System is defined elsewhere. I'm using checkboxes in the _form view to select which of the valid modes is actually set in imodes and omodes . I don't want to create new Modes from this view, just select from a list of pre-defined Modes. Below is what I'm currently using in my _form view. It generates a list of checkboxes, one for each allowed Mode for the System being edited. If the checkbox is ticked then that Mode is to be included in the imodes list. <% @allowed_modes.each do |mode| %> <li> <%= check_box_tag :imode_ids, mode.id, @system.imodes.include?(modifier), :name => 'imode_ids[]' %> <%= mode.name %> </li> <% end %> Which passes this into the controller in params: { ..., "imode_ids"=>["2", "14"], ... } In the controller#create I extract and assign the Modes that had their corresponding checkboxes ticked and add them to imodes with the following code: @system = System.new(params[:system]) # Note the the empty list that makes sure we clear the # list if none of the checkboxes are ticked if params.has_key?(:imode_ids) imodes = Mode.find(params[:imode_ids]) else imodes = [] end @system.imodes = imodes Once again that all works nicely but I'll have to copy that cludgey code into the other methods in the controller and I'd much prefer to use something more magical if possible. I feel like I've passed off the path of nice clean rails code and into the forest of "hacking around" rails; it works but I don't like it. What should I have done?

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  • Hardware recommendations / parts list for a modern, quiet ZFS NAS box - 2011-Feb edition [closed]

    - by dandv
    I want to build some really reliable storage for my data, and it seems that ZFS is the only filesystem at the moment that does live checksumming. That rules out DroboPro, so I'm looking to building a quiet ZFS NAS that would start with 4 2TB or larger hard drives. I'd like this system to be very reliable and relatively future-proof for 2-3 years, so I'm willing to invest some $$$ and buy higher end components. I did see questions here and on other forums about low-cost servers, but I'm not looking for those. I'd be super happy to go for an off-the-shelf solution, but I haven't found one that's quiet. I started doing the research (summarized on my wiki), but I realized that it just gets too complicated for what I know as a software dude, and I'm entering the analysis paralysis area. At this point, I'm basically looking for a parts list for a configuration that will work (and is modern), and I know there are folks around here who are way more competent than me. I've built computers and am comfortable assembling one and messing with *nix; I can follow guides; I just want to end the decision process for the hardware and software configuration. What I've researched so far (not that these are very modern components): Case: I think I've settled on the Antec Twelve Hundred case because it cools well, is quiet, and simply has 12 bays that allow elastic mounting. The SilverStone Raven is its counter-candidate, but I find its construction quite odd. For the PSU, I'm torn between Antec CP-850 and Nexus RX-8500, but I did this research more than a year ago. The Nexus has a very uniform power profile, and I'd rather not have the Antec spin up and down based on load. On the other hand, I'm not sure how often my file server will draw more than 400W under use. For the hard drives, I've read that WD Black drives are actually WD RE3 with a software setting changed. I'd also like to buy different drive types, not just 4 WDs. Recommendations? Right now I have a 2TB Hitachi Deskstar 7K300. For the motherboard, CPU and RAM I have no idea, other than the RAM must be ECC. I already asked a question here about ECC RAM, but I was misguided and was looking for a motherboard that would support USB 3.0 as well. I've learned to go with eSATA, or worry about USB later. Then there's the (liquid) cooling, Wi-Fi card, and FreeBSD vs. OpenSolaris Express. Lastly, I'm wondering if I can make this PC into a media server by adding a Blu-ray drive and a good sound card. But support for Blu-Ray is spotty on Linux, and I don't know if Windows 7 on VirtualBox would get sufficient hardware access to output HDMI or SPDIFF signals. (Running OpenSolaris virtualized is not an option because of the reliability risk.) Then there are HDCP concerns. Suggestions on that would be appreciated as well, but I don't want us to get sidetracked. A specific shopping list on the core components would be great, so I can start ordering, and in the meantime educate myself with regards to the other issues. Finally, I think this could become a great FAQ for those technically inclined to build their own ZFS server, but confused by the dizzying array of options out there, and I promise to compile the results and share my experience building and benchmarking the server.

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  • I need to order a list that is dependant on another list. how to change both lists?

    - by Ben Fossen
    I have a Matlab program that generates a list x = 6.1692 8.1863 5.8092 8.2754 6.0891 the program also outputs another list aspl = 680 637 669 599 693. The two lists are on equal length and the first element in list x is related to the first element in list aspl. I need to graph the two lists but want list aspl to be in order from smallest to largest. How would I go about doing this? If I need to move the first element in aspl to position 4 in the list, then the first element of list x also needs to be moved to position 4 in list x. The numbers above are not important they are just examples, the actual program generates hundereds of numbers. for example x = 6.1692 8.1863 5.8092 8.2754 initially aspl = 680 637 669 599 693 after changing aspl to ascending order this is how x should look. x = 5.8092 8.1863 5.8092 6.1692 8.2754 aspl = 599 637 669 680 693

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  • how to make css submenu stay put when subpage has been selected.

    - by Ronedog
    I have a css horizontal menu with a menu / submenu display working on the hover, but I would also like to make the submenu options stay put when I've selected that page. The code below shows the submenu on hover, but goes away on mouse out. I'm having some difficulty figuring out how to make my code work to keep the submenu items staying put? How can I do this? Thanks for your help. Here's the HTML: <ul id="menu_nav"> <li> <a href="#" class="button">Home</a> <span> <a href="#">Home Link1</a> <a href="#">Home Link2</a> <a href="#">Home Link3</a> </span> </li> <li> <a href="#" class="button">About Us</a> <span> <a href="#">About Link1</a> <a href="#">About Link2</a> <a href="#">About Link3</a> </span> </li> </ul> Here's the CSS ul#menu_nav { position:relative; float:left; width:790px; padding:0; margin:0; list-style-type:none; background-color:#000099; } ul#menu_nav li {float: left; margin: 0; padding: 0; border-right: 1px solid #555;} ul#menu_nav li a.button { float:left; text-decoration:none; color:white; background-color:#000099; padding:0.2em 0.6em; border-right:1px solid #CCCCCC; font-family: Tahoma; font-size: 11px; font-style: normal; font-weight: bold; position: relative; height: 21px; line-height:1.85em; } ul#menu_nav li a:hover { background-color:#F7F7F7; color:#000099; border-top:1px solid #CCCCCC; } ul#menu_nav li span{ float: left; padding: 15px 0; position: absolute; left: 0; top:25px; display: none; /*--Hide by default--*/ width: 790px; background: #F7F7F7; color: #fff; } ul#menu_nav li:hover span { display: block; } /*--Show subnav on hover--*/ ul#menu_nav li span a { display: inline; } /*--Since we declared a link style on the parent list link, we will correct it back to its original state--*/ ul#menu_nav li span a:hover {text-decoration: underline;} Heres the jquery: $("ul#menu_nav li").hover(function() { //Hover over event on list item $(this).css({ 'background' : '#1376c9'}); //Add background color and image on hovered list item $(this).find("span").show(); //Show the subnav } , function() { //on hover out... $(this).css({ 'background' : 'none'}); //Ditch the background $(this).find("span").hide(); //Hide the subnav });

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  • jquery nested sortable list

    - by Y.G.J
    i have this code $(document).ready(function() { $("#test-list").sortable({ items: "> li", handle : '.handle', axis: 'y', opacity: 0.6, update : function () { var order = $('#test-list').sortable('serialize'); $("#info").load("process-sortable.asp?"+order+"&id=catid&order=orderid&table=tblCats"); } }); $("#test-sub").sortable({ containment: "ul", items: "li", handle : '.handle', axis: 'y', opacity: 0.6, update : function () { var order = $('#test-list').sortable('serialize'); $("#info").load("process-sortable.asp?"+order+"&id=catid&order=orderid&table=tblCats"); } }); }); for this kind of UL <ul id="test-list"> <li></li> <li> <ul id="test-sub"> <li></li> <li></li> <li></li> <li></li> <li></li> <li></li> </ul> </li> <li></li> <li></li> <li></li> <li></li> </ul> but it can be changed dynamiclly... when i drag and drop the main li it is working when i do it with the childs it will drag the main one what is wrong?

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  • Android: ListActivity design - changing the content of the List Adapter

    - by Rob
    Hi, I would like to write a rather simple content application which displays a list of textual items (along with a small pic). I have a standard menu in which each menu item represents a different category of textual items (news, sports, leisure etc.). Pressing a menu item will display a list of textual items of this category. Now, having a separate ListActivity for each category seems like an overkill (or does it?..) Naturally, it makes much more sense to use one ListActivity and replace the data of its adapter when each category is loaded. My concern is when "back" is pressed. The adapter is loaded with items of the current category and now I need to display list of the previous category (and enable clicking on list items too...). Since I have only one activity - I thought of backup and load mechanism in onPause() and onResume() functions as well as making some distinction whether these function are invoked as a result of a "new" event (menu item selected) or by a "back" press. This seems very cumbersome for such a trivial usage... Am I missing something here? Thanks, Rob

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  • Scrollable list items in jQuery

    - by Giles B
    Hi Guys, I have a list of 4 items and the ul has a background image that makes the second item look as though it has an arrow behind it. I want to be able to scroll the items up or down when they are clicked to the second items position so for example when I click the fourth item the whole list scrolls up so the fourth item is then postioned over the top of the background image and all the other items will be sitting in the same order above it. I have tried using jQuery Tools with the circular option selected but it clones the first an last item and i end up with a gap when i get to the bottom and I also cant make each item selectable to scroll the list up or down. Here is the code for the list <div id="priceGuide"> <ul id="priceRegion"> <li><a href="#">North & Midlands</a></li> <li><a href="#">London, north of the river</a></li> <li><a href="#">London, south of the river</a></li> <li><a href="#">South & South East</a></li> </ul><!-- /priceRegion --> </div><!-- /priceGuide --> Any help is most appreciated. Thanks Giles

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  • Using a profile property of type List in .NET Membership

    - by hancock
    Hi, I'm working on a C# Webservice that needs to provide authentication as well as roles and profile management. I need each profile to have a property of type List. The profile section in the web.config looks like this: <profile defaultProvider="MyProfileProvider" enabled="true"> <providers> <remove name="MyProfileProvider"/> <add connectionStringName="MySqlServer" applicationName="MyApp" name="MyProfileProvider" type="System.Web.Profile.SqlProfileProvider" /> </providers> <properties> <add name="Websites" type="System.Collections.Generic.List&lt;String&gt;" serializeAs="Binary"/> </properties> </profile> However, when I start the webservice and try to access that property it returns the following error: System.Configuration.ConfigurationErrorsException: Attempting to load this property's type resulted in the following error: Could not load type 'System.Collections.Generic.List<String>'. (C:\Projects\MyProject\web.config line 58) --- System.Web.HttpException: Could not load type 'System.Collections.Generic.List<String>'. Is there a way to use a generic collection for this purpose?

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  • MySQL get list of unique items in a SET

    - by The Disintegrator
    I have a products table with a column of type SET (called especialidad), with these possible values. [0] => NADA [1] => Freestyle / BMX [2] => Street / Dirt [3] => XC / Rural Bike [4] => All Mountain [5] => Freeride / Downhill / Dual / 4x [6] => Ruta / Triathlon / Pista [7] => Comfort / City / Paseo [8] => Kids [9] => Playera / Chopper / Custom [10] => MTB recreacion [11] => Spinning / Fitness Any given product can have one or many of these i/e "Freestyle / BMX,Street / Dirt" Given a subset of the rows, I need to get a list of all the present "especialidad" values. But I need a list to be exploded and unique Article1: "Freestyle / BMX,Street / Dirt" Article2: "Street / Dirt,Kids" Article2: "Kids" Article4: "Street / Dirt,All Mountain" Article5: "Street / Dirt" I need a list like this Freestyle / BMX Street / Dirt" Kids" All Mountain" I tried with group_concat(UNIQUE) but I get a list of the permutations...

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  • python-xmpp and looping through list of recipients to receive and IM message

    - by David
    I can't figure out the problem and want some input as to whether my Python code is incorrect, or if this is an issue or design limitation of Python XMPP library. I'm new to Python by the way. Here's snippets of code in question below. What I'd like to do is read in a text file of IM recipients, one recipient per line, in XMPP/Jabber ID format. This is read into a Python list variable. I then instantiate an XMPP client session and loop through the list of recipients and send a message to each recipient. Then sleep some time and repeat test. This is for load testing the IM client of recipients as well as IM server. There is code to alternately handle case of taking only one recipient from command line input instead of from file. What ends up happening is that Python does iterate/loop through the list but only last recipient in list receives message. Switch order of recipients to verify. Kind of looks like Python XMPP library is not sending it out right, or I'm missing a step with the library calls, because the debug print statements during runtime indicate the looping works correctly. recipient = "" delay = 60 useFile = False recList = [] ... elif (sys.argv[i] == '-t'): recipient = sys.argv[i+1] useFile = False elif (sys.argv[i] == '-tf'): fil = open(sys.argv[i+1], 'r') recList = fil.readlines() fil.close() useFile = True ... # disable debug msgs cnx = xmpp.Client(svr,debug=[]) cnx.connect(server=(svr,5223)) cnx.auth(user,pwd,'imbot') cnx.sendInitPresence() while (True): if useFile: for listUser in recList: cnx.send(xmpp.Message(listUser,msg+str(msgCounter))) print "sending to "+listUser+" msg = "+msg+str(msgCounter) else: cnx.send(xmpp.Message(recipient,msg+str(msgCounter))) msgCounter += 1 time.sleep(delay)

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  • MVC nhibernate entiry mapping for dropdown list

    - by Rod McLeay
    Hi, I have a dropdown list on an ASP.NET MVC project that I am pretty sure is not binding to my model because of my nhibernate mapping. I have tried many variations on the asp mvc side resulting in this post here. MVC side of things seems fine I believe the issue may be that my object is trying to bind, but my mapping is out of whack. My mapping is: <many-to-one name="Project" lazy="false" class="AgileThought.ERP.Domain.Property.Project" column="ProjectGUID" /> My View gives an error saying that the GUID from the dropdownList selected value is not valid. Which I think may be that it is trying to push the GUID into my related project object. The value 'fd38c877-706f-431d-b624-1269184eeeb5' is invalid. My related project list binds to the dropdown list just fine, it is just not binding to my models Project entity. Does the related Project entity need to know about its relationship? Its really just a lookup list. Many thanks for your time and best regards, Rod

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  • Display an Android Sensors List

    - by Skatephone
    I'm trying to display a list of available sensors but it's like there are not! I was thinking that it was because of the emulator, but i tried it on the phone and the result is the same. private SensorManager mSensorManager; TextView mSensorsTot,mSensorAvailables; ...... public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); // Get the texts fields of the layout and setup to invisible mSensorsTot = (TextView) findViewById(R.id.sensoritot); mSensorAvailables = (TextView) findViewById(R.id.sensoridisponibili); // Get the SensorManager mSensorManager= (SensorManager) getSystemService(SENSOR_SERVICE); // List of Sensors Available List<Sensor> msensorList = mSensorManager.getSensorList(SensorManager.SENSOR_ALL); // Print how may Sensors are there mSensorsTot.setText(msensorList.size()+" "+this.getString(R.string.sensors)+"!"); // Print each Sensor available using sSensList as the String to be printed String sSensList = new String(""); Sensor tmp; int x,i; for (i=0;i<msensorList.size();i++){ tmp = msensorList.get(i); sSensList = " "+sSensList+tmp.getName(); // Add the sensor name to the string of sensors available } // if there are sensors available show the list if (i>0){ sSensList = getString(R.string.sensors)+":"+sSensList; mSensorAvailables.setText(sSensList); } } Thank's Valerio From Italy :)

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