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  • .NET XmlSerializer fails with List<T>

    - by Redshirt
    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<T> then I have no problems saving/loading the xml file. What am I doing wrong? // 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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  • C++ keeping a list of objects and calling a contructor through another function

    - by Nona Urbiz
    why isnt my object being created? When I do it like so, I am told error C2065: 'AllReferrals' : undeclared identifier as well as error C2228: left of '.push_back' must have class/struct/union. If I put the list initialization before the class I get error C2065: 'AllReferrals' : undeclared identifier. Thanks! #include <iostream> #include <fstream> #include <regex> #include <string> #include <list> #include <map> using namespace std; using namespace tr1; class Referral { public: string url; map<string, int> keywords; static bool submit(string url, string keyword, int occurrences) { //if(lots of things i'll later add){ Referral(url, keyword, occurrences); return true; //} //else // return false; } private: list<string> urls; Referral(string url, string keyword, int occurrences) { url = url; keywords[keyword] = occurrences; AllReferrals.push_back(this); } }; static list<Referral> AllReferrals; int main() { Referral::submit("url", "keyword", 1); cout << AllReferrals.size(); cout << "\n why does that ^^ say 0 (help me make it say one)?"; cout << "\n and how can i AllReferrals.push_back(this) from my constructor?"; cout << " When I do it like so, I am told error C2065: 'AllReferrals' : undeclared identifier"; cout << " as well as error C2228: left of '.push_back' must have class/struct/union."; cout << " If I put the list initialization before the class I get error C2065: 'AllReferrals' : undeclared identifier."; cout << "\n\n\t Thanks!"; getchar(); }

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  • Java Sorting "queue" list based on DateTime and Z Position (part of school project)

    - by Kuchinawa
    For a school project i have a list of 50k containers that arrive on a boat. These containers need to be sorted in a list in such a way that the earliest departure DateTimes are at the top and the containers above those above them. This list then gets used for a crane that picks them up in order. I started out with 2 Collection.sort() methods: 1st one to get them in the right XYZ order Collections.sort(containers, new Comparator<ContainerData>() { @Override public int compare(ContainerData contData1, ContainerData contData2) { return positionSort(contData1.getLocation(),contData2.getLocation()); } }); Then another one to reorder the dates while keeping the position in mind: Collections.sort(containers, new Comparator<ContainerData>() { @Override public int compare(ContainerData contData1, ContainerData contData2) { int c = contData1.getLeaveDateTimeFrom().compareTo(contData2.getLeaveDateTimeFrom()); int p = positionSort2(contData1.getLocation(), contData2.getLocation()); if(p != 0) c = p; return c; } }); But i never got this method to work.. What i got working now is rather quick and dirty and takes a long time to process (50seconds for all 50k): First a sort on DateTime: Collections.sort(containers, new Comparator<ContainerData>() { @Override public int compare(ContainerData contData1, ContainerData contData2) { return contData1.getLeaveDateTimeFrom().compareTo(contData2.getLeaveDateTimeFrom()); } }); Then a correction function that bumps top containers up: containers = stackCorrection(containers); private static List<ContainerData> stackCorrection(List<ContainerData> sortedContainerList) { for(int i = 0; i < sortedContainerList.size(); i++) { ContainerData current = sortedContainerList.get(i); // 5 = Max Stack (0 index) if(current.getLocation().getZ() < 5) { //Loop through possible containers above current for(int j = 5; j > current.getLocation().getZ(); --j) { //Search for container above for(int k = i + 1; k < sortedContainerList.size(); ++k) if(sortedContainerList.get(k).getLocation().getX() == current.getLocation().getX()) { if(sortedContainerList.get(k).getLocation().getY() == current.getLocation().getY()) { if(sortedContainerList.get(k).getLocation().getZ() == j) { //Found -> move container above current sortedContainerList.add(i, sortedContainerList.remove(k)); k = sortedContainerList.size(); i++; } } } } } } return sortedContainerList; } I would like to implement this in a better/faster way. So any hints are appreciated. :)

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  • c# linq to xml to list

    - by WtFudgE
    I was wondering if there is a way to get a list of results into a list with linq to xml. If I would have the following xml for example: <?xml version="1.0"?> <Sports xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema"> <SportPages> <SportPage type="test"> <LinkPage> <IDList> <string>1</string> <string>2</string> </IDList> </LinkPage> </SportPage> </SportPages> </Sports> How could I get a list of strings from the IDList? I'm fairly new to linq to xml so I just tried some stuff out, I'm currently at this point: var IDs = from sportpage in xDoc.Descendants("SportPages").Descendants("SportPage") where sportpage.Attribute("type").Value == "Karate" select new { ID = sportpage.Element("LinkPage").Element("IDList").Elements("string") }; But the var is to chaotic to read decently. Isn't there a way I could just get a list of strings from this? Thanks

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  • jQuery - manipulate dropped element in sortable list

    - by WastedSpace
    Hi there, I have a draggable list (.field) where you can drag & drop items from it into a sortable list (.sortlist). I did it this way because I didn't want the master list (.field) altered in any way. It works fine, except I cannot work out how to manipulate the dropped field in a sortable list. I can do it from a draggable into a droppable area by using the following in a function for 'drop:' in droppable(): $(this).append('html code here to change content of dragged field'); However this doesn't work inside a sortable(). My code looks like this: $(".sortlist").sortable({ receive: function(event, ui) { var dropElemTxt = $(ui.item).text(); var dropElemId = $(ui.item).attr('id'); $(ui.item).replaceWith('<li class="box" id="'+dropElemId+'">Updated field! '+dropElemTxt+'</li>'); } }); $(ui.item).replaceWith changes the master field that was being dragged, so this doesn't work. And I tried $(this).replaceWith, but that updates the sortable area (.sortlist). Any idea what code I need to reference the dragged item? Many thanks, Ali.

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  • adjacency list creation , out of Memory error

    - by p1
    Hello , I am trying to create an adjacency list to store a graph.The implementation works fine while storing 100,000 records. However,when I tried to store around 1million records I ran into OutofMemory Error : Exception in thread "main" java.lang.OutOfMemoryError: Java heap space at java.util.Arrays.copyOfRange(Arrays.java:3209) at java.lang.String.(String.java:215) at java.io.BufferedReader.readLine(BufferedReader.java:331) at java.io.BufferedReader.readLine(BufferedReader.java:362) at liarliar.main(liarliar.java:39) Following is my implementation HashMap<String,ArrayList<String>> adj = new HashMap<String,ArrayList<String>>(num); while ((str = in.readLine()) != null) { StringTokenizer Tok = new StringTokenizer(str); name = (String) Tok.nextElement(); cnt = Integer.valueOf(Tok.nextToken()); ArrayList<String> templist = new ArrayList<String>(cnt); while(cnt>0) { templist.add(in.readLine()); cnt--; } adj.put(name,templist); } //done creating a adjacency list I am wondering, if there is any better way to implement the adjacency list. Also, I know number of nodes right in the begining and , in the future I flatten the list as I visit nodes. Any suggestions ? Thanks

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  • Most efficient way of creating tree from adjacency list

    - by Jeff Meatball Yang
    I have an adjacency list of objects (rows loaded from SQL database with the key and it's parent key) that I need to use to build an unordered tree. It's guaranteed to not have cycles. This is taking wayyy too long (processed only ~3K out of 870K nodes in about 5 minutes). Running on my workstation Core 2 Duo with plenty of RAM. Any ideas on how to make this faster? public class StampHierarchy { private StampNode _root; private SortedList<int, StampNode> _keyNodeIndex; // takes a list of nodes and builds a tree // starting at _root private void BuildHierarchy(List<StampNode> nodes) { Stack<StampNode> processor = new Stack<StampNode>(); _keyNodeIndex = new SortedList<int, StampNode>(nodes.Count); // find the root _root = nodes.Find(n => n.Parent == 0); // find children... processor.Push(_root); while (processor.Count != 0) { StampNode current = processor.Pop(); // keep a direct link to the node via the key _keyNodeIndex.Add(current.Key, current); // add children current.Children.AddRange(nodes.Where(n => n.Parent == current.Key)); // queue the children foreach (StampNode child in current.Children) { processor.Push(child); nodes.Remove(child); // thought this might help the Where above } } } } public class StampNode { // properties: int Key, int Parent, string Name, List<StampNode> Children }

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  • Remove duplicates from a list of nested dictionaries

    - by user2924306
    I'm writing my first python program to manage users in Atlassian On Demand using their RESTful API. I call the users/search?username= API to retrieve lists of users, which returns JSON. The results is a list of complex dictionary types that look something like this: [ { "self": "http://www.example.com/jira/rest/api/2/user?username=fred", "name": "fred", "avatarUrls": { "24x24": "http://www.example.com/jira/secure/useravatar?size=small&ownerId=fred", "16x16": "http://www.example.com/jira/secure/useravatar?size=xsmall&ownerId=fred", "32x32": "http://www.example.com/jira/secure/useravatar?size=medium&ownerId=fred", "48x48": "http://www.example.com/jira/secure/useravatar?size=large&ownerId=fred" }, "displayName": "Fred F. User", "active": false }, { "self": "http://www.example.com/jira/rest/api/2/user?username=andrew", "name": "andrew", "avatarUrls": { "24x24": "http://www.example.com/jira/secure/useravatar?size=small&ownerId=andrew", "16x16": "http://www.example.com/jira/secure/useravatar?size=xsmall&ownerId=andrew", "32x32": "http://www.example.com/jira/secure/useravatar?size=medium&ownerId=andrew", "48x48": "http://www.example.com/jira/secure/useravatar?size=large&ownerId=andrew" }, "displayName": "Andrew Anderson", "active": false } ] I'm calling this multiple times and thus getting duplicate people in my results. I have been searching and reading but cannot figure out how to deduplicate this list. I figured out how to sort this list using a lambda function. I realize I could sort the list, then iterate and delete duplicates. I'm thinking there must be a more elegant solution. Thank you!

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  • How to move list items from two lists (from different areas) to one specific list by clicking the li

    - by pschorr
    I've been having some issues setting up a list of items and moving them between each other. Is it possible to have multiple lists, with a link inside each item to move it to a specified list? i.e. List of actions with a plus next to the action, click the plus and move to a specified box? Furthermore, would it be possible to then load a lightbox (code would have to be inline I'd guess) from that page and move those names to the specific list as well? Example Images Thanks much! More broad view of my efforts so far... The initial issue being that I could not use listboxes due to their being rendered natively inside each individual browser. Through listboxes I was able to set this up, but with a trigger via the code below (found on stackoverflow). While it gave me partial functionality it did not get the target I was looking for. document.getElementById('moveTrigger').onclick = function() { var listTwo = document.getElementById('secondList'); var options = document.getElementById('firstList').getElementsByTagName('option'); while(options.length != 0) { listTwo.appendChild(options[0]); } } I then moved onto jqueryui's sortable and it's ability to connect multiple, and most important, style-able lists and to be dragged between each other. This works for the side by side tables, but it does not offer the usability I was looking for overall. So, I've come to where I'm unsure as to where to move forward. While I can get around PHP, I wouldn't know where to start with this one personally. I'm open to any and all options! Thanks much!

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  • Flex custom list selection not highlighting

    - by aip.cd.aish
    I want to create a custom list in Flex for an interface prototype. The list is supposed to have an image and 3 text fields. This is what I have done so far, the control displayed is what I want. But, when I click on one of the items, the item does not appear (visually) to be selected. I was not sure how I would implement this. Here is my code so far: <s:List width="400" height="220" dataProvider="{arrColl}" alternatingItemColors="[#EEEEEE, white]"> <s:itemRenderer> <fx:Component> <mx:Canvas height="100"> <mx:Image height="90" width="120" source="{data.imageSource}"></mx:Image> <mx:Label left="125" y="10" text="{data.title}" /> <mx:Label left="125" y="30" text="{data.type}" /> <mx:Label left="125" y="50" text="{data.description}" /> </mx:Canvas> </fx:Component> </s:itemRenderer> </s:List>

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  • Appending unique values only in a linked list in C

    - by LuckySlevin
    typedef struct child {int count; char word[100]; inner_list*next;} child; typedef struct parent { char data [100]; inner_list * head; int count; outer_list * next; } parent; void append(child **q,char num[100],int size) { child *temp,*r,*temp2,*temp3; parent *out=NULL; temp = *q; temp2 = *q; temp3 = *q; char *str; if(*q==NULL) { temp = (child *)malloc(sizeof(child)); strcpy(temp->word,num); temp->count =size; temp->next=NULL; *q=temp; } else { temp = *q; while(temp->next !=NULL) { temp=temp->next; } r = (child *)malloc(sizeof(child)); strcpy(r->word,num); r->count = size; r->next=NULL; temp->next=r; } } This is my append function which I use for adding an element to my child list. But my problem is it only should append unique values which are followed by a string. Which means : Inputs : aaa bbb aaa ccc aaa bbb ccc aaa Append should act : For aaa string there should be a list like bbb->ccc(Not bbb->ccc->bbb since bbb is already there if bbb is coming more than one time it should be increase count only.) For bbb string there should be list like aaa->ccc only For ccc string there should be list like aaa only I hope i could make myself clear. Is there any ideas? Please ask for further info.

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  • Handling Apache Thrift list/map Return Types in C++

    - by initzero
    First off, I'll say I'm not the most competent C++ programmer, but I'm learning, and enjoying the power of Thrift. I've implemented a Thrift Service with some basic functions that return void, i32, and list. I'm using a Python client controlled by a Django web app to make RPC calls and it works pretty well. The generated code is pretty straight forward, except for list returns: namespace cpp Remote enum N_PROTO { N_TCP, N_UDP, N_ANY } service Rcon { i32 ping() i32 KillFlows() i32 RestartDispatch() i32 PrintActiveFlows() i32 PrintActiveListeners(1:i32 proto) list<string> ListAllFlows() } The generated signatures from Rcon.h: int32_t ping(); int32_t KillFlows(); int32_t RestartDispatch(); int32_t PrintActiveFlows(); int32_t PrintActiveListeners(const int32_t proto); int64_t ListenerBytesReceived(const int32_t id); void ListAllFlows(std::vector<std::string> & _return); As you see, the ListAllFlows() function generated takes a reference to a vector of strings. I guess I expect it to return a vector of strings as laid out in the .thrift description. I'm wondering if I am meant to provide the function a vector of strings to modify and then Thrift will handle returning it to my client despite the function returning void. I can find absolutely no resources or example usages of Thrift list< types in C++. Any guidance would be appreciated.

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  • Working with a list, performing arithmetic logic in Python

    - by haea ohoh
    Suppose I have made a large list of numbers, and I want to make another one which I will add, pairwise, with the first list. Here's the first list, A: [109, 77, 57, 34, 94, 68, 96, 72, 39, 67, 49, 71, 121, 89, 61, 84, 45, 40, 104, 68, 54, 60, 68, 62, 91, 45, 41, 118, 44, 35, 53, 86, 41, 63, 111, 112, 54, 34, 52, 72, 111, 113, 47, 91, 107, 114, 105, 91, 57, 86, 32, 109, 84, 85, 114, 48, 105, 109, 68, 57, 78, 111, 64, 55, 97, 85, 40, 100, 74, 34, 94, 78, 57, 77, 94, 46, 95, 60, 42, 44, 68, 89, 113, 66, 112, 60, 40, 110, 89, 105, 113, 90, 73, 44, 39, 55, 108, 110, 64, 108] And here's B: [35, 106, 55, 61, 81, 109, 82, 85, 71, 55, 59, 38, 112, 92, 59, 37, 46, 55, 89, 63, 73, 119, 70, 76, 100, 49, 117, 77, 37, 62, 65, 115, 93, 34, 107, 102, 91, 58, 82, 119, 75, 117, 34, 112, 121, 58, 79, 69, 68, 72, 110, 43, 111, 51, 102, 39, 52, 62, 75, 118, 62, 46, 74, 77, 82, 81, 36, 87, 80, 56, 47, 41, 92, 102, 101, 66, 109, 108, 97, 49, 72, 74, 93, 114, 55, 116, 66, 93, 56, 56, 93, 99, 96, 115, 93, 111, 57, 105, 35, 99] How might I generate the arithmatic addition logic, processing each pairwise value one by one (A[0] and B[0], through A[99], B[99]) and producing the list C (A[0] + B[0] through A[99]+ B[99])?

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  • Creating a dictionary with list of lists in Python

    - by ghbhatt
    I have a huge file (with around 200k inputs). The inputs are in the form: A B C D B E F C A B D D I am reading this file and storing it in a list as follows: text = f.read().split('\n') This splits the file whenever it sees a new line. Hence text is like follows: [[A B C D] [B E F] [C A B D] [D]] I have to now store these values in a dictionary where the key values are the first element from each list. i.e the keys will be A, B, C, D. I am finding it difficult to enter the values as the remaining elements of the list. i.e the dictionary should look like: {A: B C D; B: E F; C: A B D; D: 0} I have done the following: inlinkDict = {} for doc in text: adoc= doc.split(' ') docid = adoc[0] inlinkDict[docid] = inlinkDict.get(docid,0) + {I do not understand what to put in here} Please help as to how should i add the values to my dictionary. It should be 0 if there are no elements in the list except for the one which will be the key value. Like in example for 0.

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  • How to update data in the user information list when using FBA

    - by Flo
    I've got to support a SharePoint web application which uses FBA with a custom membership and a custom role provider to authenticate the user against two different LDAPs. The user data are only stored in the user information lists. The SSP user profiles are not used. Now one of the users got married and therefore her surname got changed in the LDAP (the one where her information are stored). But this change doesn't get provisioned into the user information list. I wondering what option I have to provision changes of user data to the user information list. I've already tried to update the last name of the user manually, but it seems as if certain information like surname, first name are not editable in the user information list. I tried to edit them as a site administrator. So what option do I have to solve this problem? Being able to edit the information per hand would also be a solution but of course not the most preferred one.

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  • Searching a large list of words in another large list

    - by Christian
    I have a list of 1,000,000 strings with a maximum length of 256 with protein names. Every string has an associated ID. I have another list of 4,000,000,000 strings with a maximum length of 256 with words out of articles and every word has an ID. I want to find all matches between the list of protein names and the list of words of the articles. Which algorithm should I use? Should I use some prebuild API? It would be good if the algorithm runs on a normal PC without special hardware.

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  • Make list from two database items

    - by unnamet
    I want to make a list from some data that I have in my database. The first two sets of data in my database are first name and last name. I want my list to show both first and last name instead of now where it only shows the first name. How do I do that? My code looks like this: private void fillData() { Cursor contactCursor = mDbHelper.fetchAllReminders(); startManagingCursor(contactCursor); String[] from = new String[]{DbAdapter.KEY_FIRST}; int[] to = new int[]{R.id.contactlist}; SimpleCursorAdapter contacts = new SimpleCursorAdapter(this, R.layout.list, contactCursor, from, to); setListAdapter(contacts); }

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  • Rails and Searchlogic: finding products that matching all given product categories by using searchlo

    - by Roland
    I have a model Publication and a model Category in my Rails app. Both are connected with a has_and_belongs_to_many association. Now I would like to search publications that match one or more categories. If more than one category is given they have all assigned to the publication. I want to specify the categories in a multiple select_box. Publication.released.categories_id_is([1,2]) is not working because the categories are connected with OR. With Publication.categories_id_is_all([1,2]) the categories are connected with AND, but no result is given back. Any idea's on that? Am I mising the right point in the docs. Thanks for your very welcome help!

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  • Python 3: unpack inner lists in list comprehension

    - by Beau Martínez
    I'm running the following code on a list of strings to return a list of its words: words = [re.split('\\s+', line) for line in lines] However, I end up getting something like: [['import', 're', ''], ['', ''], ['def', 'word_count(filename):', ''], ...] As opposed to the desired: ['import', 're', '', '', '', 'def', 'word_count(filename):', '', ...] How can I unpack the lists re.split('\\s+', line) produces in the above list comprehension? Naïvely, I tried using * but that doesn't work. (I'm looking for a simple and Pythonic way of doing; I was tempted to write a function but I'm sure the language accommodates for this issue.)

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  • Comparing two List<MyClass> in C#

    - by Matt
    I have a class called MyClass This class inherits IEquatable and implements equals the way I need it to. (Meaning: when I compare two MyClass tyupe objects individually in code, it works) I then create two List: var ListA = new List<MyClass>(); var ListB = new List<MyClass>(); // Add distinct objects that are equal to one another to // ListA and ListB in such a way that they are not added in the same order. When I go to compare ListA and ListB, should I get true? ListA.Equals(ListB)==true; //???

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  • Converting array to list in Java

    - by Alexandru
    How do I convert an array to a list in Java? I used the Arrays.asList() but the behavior (and signature) somehow changed from 1.4.2 to 1.5.0 and most snippets I found on the web use the 1.4.2 behaviour. For example: int[] spam = new int[] { 1, 2, 3 }; Arrays.asList(spam) on 1.4.2 returns a list containing the elements 1, 2, 3 on 1.5.0 returns a list containing the array spam In many cases it should be easy to detect, but sometimes it can slip unnoticed: Assert.assertTrue(Arrays.asList(spam).indexOf(4) == -1);

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  • Sorting list of URLs by length in Jython

    - by Eef
    Hi, I am writing a Jython script to sort a list of URLs. I have a list that looks like this: http://www.domain.com/folder1/folder2/|,1 http://www.domain.com/folder1/|,1 http://www.domain.com/folder1/folder2/folder3/|,1 http://www.domain.com/folder1/|,1 http://www.domain.com/folder1/folder2/|,1 http://www.domain.com/folder1/folder2/|,1 http://www.domain.com/folder1/folder2/folder3/|,1 The pipe and the comma separates the path from the amount of files that are under that path. Is it possible some how use Jython to order the URLs by length, so it would end up look like the below list: http://www.domain.com/folder1/|,1 http://www.domain.com/folder1/|,1 http://www.domain.com/folder1/folder2/|,1 http://www.domain.com/folder1/folder2/|,1 http://www.domain.com/folder1/folder2/|,1 http://www.domain.com/folder1/folder2/folder3/|,1 http://www.domain.com/folder1/folder2/folder3/|,1 Hope you guys get what I mean, any help would be appreciated. Cheers

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  • Racket list in struct

    - by Tim
    I just started programming with Racket and now I have the following problem. I have a struct with a list and I have to add up all prices in the list. (define-struct item (name category price)) (define some-items (list (make-item "Book1" 'Book 40.97) (make-item "Book2" 'Book 5.99) (make-item "Book3" 'Book 20.60) (make-item "Item" 'KitchenAccessory 2669.90))) I know that I can return the price with: (item-price (first some-items)) or (item-price (car some-items)). The problem is, that I dont know how I can add up all Items prices with this. Answer to Óscar López: May i filled the blanks not correctly, but Racket mark the code black when I press start and don't return anything. (define (add-prices items) (if (null? items) (+ 0 items) ; Here I don't really know what to write for a 0. ; I tried differnt thnigs like null and this version. (+ (item-price (first some-items)) (add-prices (item-price (rest some-items))))))

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