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• What Can A 'TreeDict' (Or Treemap) Be Used For In Practice?

  - by Seun Osewa

  I'm developing a 'TreeDict' class in Python. This is a basically a dict that allows you to retrieve its key-value pairs in sorted order, just like the Treemap collection class in Java. I've implemented some functionality based on the way unique indexes in relational databases can be used, e.g. functions to let you retrieve values corresponding to a range of keys, keys greater than, less than or equal to a particular value in sorted order, strings or tuples that have a specific prefix in sorted order, etc. Unfortunately, I can't think of any real life problem that will require a class like this. I suspect that the reason we don't have sorted dicts in Python is that in practice they aren't required often enough to be worth it, but I want to be proved wrong. Can you think of any specific applications of a 'TreeDict'? Any real life problem that would be best solved by this data structure? I just want to know for sure whether this is worth it.

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• Scraping html WITHOUT uniquie identifiers using python

  - by Nicholas Law

  I would like to design an algorithm using python that scrapes thousands of pages like this one and this one, gathers all the data and inserts it into a MySQL database. The script will be run on a weekly or bi-weekly basis to update the database of any new information added to each individual page. Ideally I would like a scraper that is easy to work with for table structured data but also data that does not have unique identifiers (ie. id and classes attributes). Which scraper add-on should I use? BeautifulSoup, Scrapy or Mechanize? Are there any particular tutorials/books I should be looking at for this desired result? In the long-run I will be implementing a mobile app that works with all this data through querying the database.

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• Referencing text input fields in CKEditor dialogs

  - by rt-uk

  Hi, I've been playing around with this for a couple of weeks now with no success... In a CKEditor dialog, text input fields are renamed with a unique number - e.g. id: 'txtUrl' will become something like id='27_textinput'. How do I reference this? // I feel it should be something like: var myfield = CKEDITOR.instances.myElement.document.$.body.getId('txtUrl'); // or maybe: var myfield = CKEDITOR.dialog.getContentElement('info','txtUrl'); // and then: myfield.value = 'myvalue'; But these don't work. Please help! Thanks in advance, R

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• Database Design Question: GUID + Natural Numbers

  - by Alan

  For a database I'm building, I've decided to use natural numbers as the primary key. I'm aware of the advantages that GUID's allow, but looking at the data, the bulk of row's data were GUID keys. I want to generate XML records from the database data, and one problem with natural numbers is that I don't want to expose my database key's to the outside world, and allow users to guess "keys." I believe GUID's solve this problem. So, I think the solution is to generate a sparse, unique iD derived from the natural ID (hopefully it would be 2-way), or just add an extra column in the database and store a guid (or some other multibyte id) The derived value is nicer because there is no storage penalty, but it would be easier to reverse and guess compared to a GUID. I'm (buy) curious as to what others on SO have done, and what insights they have.

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• Reuse C++ Header files

  - by Amrish

  Guys, I have a Visual C++ solution with 2 projects AlgorithmA & AlgorithmB and both share a common header file RunAlgo.h with the class declaration. Each project in the solution has its own unique implementation for the header file. I am trying to compile a DLL out of the common header file RunAlgo.h and add reference to this DLL in the projects AlgorithmA & AlgorithmB. I have then included separate RunAlgo.cpp definition file in both my projects. The problem is that I am getting linker errors while compiling the new DLL project which has only the header file. So, the question is Can a header file with only class declaration be compiled into a DLL (Similar to class library containing an Interface in C#)? For the above scenario, is there a better approach to reuse the common Header file among projects? Should the above method work (re-check my code?)

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• django: Selecting questions that was not asked

  - by Oleg Tarasenko

  Hi, I am creating small django application which holds some few questions (and answers for them) What I want to do is to show user random question, but only from those which was not solved by him yet. I wonder how to do this. For now, I defined user profile model this way: class UserProfile(models.Model): rank = models.IntegerField(default = 1) solvedQ = models.ManyToManyField(Question) user = models.ForeignKey(User, unique=True) So solved problems are added this way: if user.is_authenticated(): profile = user.get_profile() profile.rank += 1 profile.solvedQ.add(Question.objects.get(id=id)) Now if the view must show random question, but not from already solved list... Is there a good way to intersect Questions and solvedQuestions.... so question is chosen from the unsolved list?

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• Qlikview joins that dosen't join on all matching column names

  - by Dev_Karl

  Hi! I'm new to Qlikview and looking for some answers regarding scripting. How can I create Qlickview joins that just join on a specific column (and not all that are having a matching name)? Let's say that I'm having the following tables: Employee Id | Person | DepartmentID | Flags 1000 , Bob , 2001 , 1000000 1001 , Sue , 2002 , 1100000 Department Id | Name | Flags 2001 , HR , 01101111 2001 , R&D , 1100000 What is the best way of joining those tables on the DepartmentID <- ID field? The data is provided by SQL selects. I'm thinking of writing SQL views using unique names would be one idea, but there must be a simpler way. Please advice Kind regards, Karl

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• importing data using get or create - identity error 1062

  - by hamackey

  I am importing data from a mssql database into mysql. Works except when it encounters the id of a previous entry. id is unique. I need to get entries that already exist so that they can be placed in the work of the day. Error is IntegrityError: (1062, "Duplicate entry '001355338' for key 2") This entry is already in the database. I need it entered for that day, but can not have it added to the table. It is already there. def handle(self, *args, **options): 59 #patients_local = Patient.objects.all() 60 #attendings_local = Attending.objects.all() 61 connection = pyodbc.connect("XXXXXXXXXXX") 62 cursor = connection.cursor() 63 cursor.execute(COMMAND) 64 rows = cursor.fetchall() 65 for row in rows: 66 # get_or_create returns (object, boolean) 67 p, created = Patient.objects.get_or_create( 68 first_name = row.Firstname, 69 middle_name = '', 70 last_name = row.Lastname, 71 id = row.id, 72 )

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• MySQL query problem

  - by Luke

  Ok, I have the following problem. I have two InnoDB tables: 'places' and 'events'. One place can have many events, but event can be created without entering place. In this case event's foreign key is NULL. Simplified structure of the tables looks as follows: CREATE TABLE IF NOT EXISTS `events` ( `id` int(11) unsigned NOT NULL AUTO_INCREMENT, `name` varchar(255) COLLATE utf8_bin NOT NULL, `places_id` int(9) unsigned DEFAULT NULL, PRIMARY KEY (`id`), KEY `fk_events_places` (`places_id`), ) ENGINE=InnoDB; ALTER TABLE `events` ADD CONSTRAINT `events_ibfk_1` FOREIGN KEY (`places_id`) REFERENCES `places` (`id`) ON DELETE CASCADE ON UPDATE NO ACTION; CREATE TABLE IF NOT EXISTS `places` ( `id` int(9) unsigned NOT NULL AUTO_INCREMENT, `name` varchar(255) COLLATE utf8_bin NOT NULL, PRIMARY KEY (`id`), ) ENGINE=InnoDB; Question is, how to construct query which contains name of the event and name of the corresponding place (or no value, in case there is no place assigned?). I am able to do it with two queries, but then I am visibly separating events which have place assigned from the ones that are without place. Help really appreciated.

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• Can a primary key be equal to a different column?

  - by eric

  I know that a primary key must be unique, but is it okay for a primary key to be equal to a different column in the same table by coincidence? For instance, I have 2 tables. One table is called person that holds information about a person (ID, email, telephone, address, name). The other table is staff (ID, pID(person ID), salary, position). In staff the ID column is the primary key and is used to uniquely identify a staff member. The number is from 1 - 100. However, the pID (person ID) may be equal to the ID. For instance the staff ID may be 1 and the pID that it references to may be equal to 1. Is that okay?

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• Generate matrix with value flags

  - by pagid

  I do have a solution for the following problem but it's quite ugly and it can most likely be done in a much shorter way. Would be great to get your help. My input looks like this: C1 C2 A B B D D C A D and my output should look like this: A B C D 1 1 0 0 0 1 0 1 0 0 1 1 1 0 0 1 My current solution is: index <- unique(unlist(input[,1:2])) output <- matrix(0,nrows=dim(input),ncols=length(index)) for(i in 1:dim(input)) { output[i, input[i,]$C1] <- 1 output[i, input[i,]$C2] <- 1 } Of course 4-5 lines is actually fine - but even as an R beginner this doesn't feel right to use a for loop. Besides that my actual data has much more than two columns, therefore this doesn't look nice in the end. How would I do that in a smarter way? Cheers

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• Windows Mobile application icon

  - by Andy White

  Is it possible to specify the application icon for a windows mobile app from a resource file or other configuration besides the .csproj? The reason I would like to do this is because I have an application that can be configured to run in several different ways. We would like to build out three unique .cabs based on these configurations, and we would like to use a different icon for each version. One option we've considered is just running multiple builds and swapping out the icon file each time, but we were hoping there would be a way to do this using a "resource" DLL or something along those lines, that could be compiled or linked in to the main .exe.

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• Best Practice for creating Web Services

  - by Holograham

  To preface I am new to web development. I am looking at creating a core set of RESTful web services around a valuable document library of sorts (initial CRUD abilities). In doing so I am theoretically creating a perfectly re-usable and scalable back-end to be used by unanticipated applications in the future. My question centers around the best practice for doing this. My initial requirement has me also creating a unique front end. Would I make the front end and back end completely separate projects to enhance the re-usability. It would increase overhead. Looking at using GWT, Restlet, and JEE technology stack if this influences the setup at all.

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• Building a linked list with LINQ

  - by FreshCode

  What is the fastest way to order an unordered list of elements by predecessor (or parent) element index using LINQ? Each element has a unique ID and the ID of that element's predecessor (or parent) element, from which a linked list can be built to represent an ordered state. Example ID | Predecessor's ID --------|-------------------- 20 | 81 81 | NULL 65 | 12 12 | 20 120 | 65 The sorted order is {81, 20, 12, 65, 120}. An (ordered) linked list can easily be assembled iteratively from these elements, but can it be done in fewer LINQ statements? Edit: I should have specified that IDs are not necessarily sequential. I chose 1 to 5 for simplicity. See updated element indices which are random.

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• Get Category in Wordpress Post

  - by Adam Beaumont

  OK I have a standard post here: http://www.ticketyoda.co.uk/concerts/rihanna-tickets/rihanna-tickets-manchester-2013-06-12-united-kingdom/970 I am trying to make each post unique and contain the category information for both the city (Manchester) and the Artist (Rihanna). At the moment the box underneath the venue contains the information taken from the category (see breadcrumb). So I have 1 out of 2. What I need now is for an extra box below to show the category information for the Artist. I use : <?php $category = get_the_category(); echo $category[0]->category_description; ?> to get the first category. You can see the rihanna description under the posts here: http://www.ticketyoda.co.uk/concerts/rihanna-tickets/ Any help appreciated.

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• How to map it? HasOne x References

  - by Felipe

  Hi everyones, I need to make a mapping One by One, and I have some doubts. I have this classes: public class DocumentType { public virtual int Id { get; set; } /* othes properties for documenttype */ public virtual DocumentConfiguration Configuration { get; set; } public DocumentType () { } } public class DocumentConfiguration { public virtual int Id { get; set; } /* some other properties for configuration */ public virtual DocumentType Type { get; set; } public DocumentConfiguration () { } } A DocumentType object has only one DocumentConfiguration, but it is not a inherits, it's only one by one and unique, to separate properties. How should be my mappings in this case ? Should I use References or HasOne ? Someone could give an example ? When I load a DocumentType object I'd like to auto load the property Configuration (in documentType). Thanks a lot guys! Cheers

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• Command Query Separation validating for retries

  - by Neil Barnwell

  So I'm comfortable with the basic concept of CQS, where you might have a command that writes to one database, and that updates the query database that you read from. However, consider the scenario where you are entering data, and want to prevent duplicates. Using new employee data entry an employee register as an example, working through a pile of application forms to key in the new employees' details: Take top sheet. Key in employee name and unique payroll number to UI. Submit. Put paper in "completed pile". Repeat. How would you now prevent the user from keying in the same payroll number again, say for instance if they get distracted and can't remember whether they've keyed one in already and the "message" hasn't got all the way back to the query db for the user to search?

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• Which video format(s) should a webapp serve?

  - by NoozNooz42

  I need to put up a few videos on a Webapp and I'm a bit lost. My requirements are: DRM is not a concern at all it should work on the iPhone (and iPad) and on the main browsers (Safari, Internet Explorer, Firefox, Opera). it is not a problem at all if the video doesn't play on Linux (because it's a video/screencast of a Windows/OS X software targetted at, well, Windows and OS X users) it is not a problem at all if it also works on Linux (I'm a Linux user myself) Can a unique format be served (like H.264) and play without any additional work on my part or do I need to convert the videos to different formats and have the webapp serve different video formats depending on the browser used? Should I use the "video" tag of HTML5 when I detect an HTML5 capable browser? What's the "safest" bet here? I take it that Flash is out of the equation seen that iPhone/iPad is a requirement.

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• Java long task - Did it stop writing to file?

  - by rockit

  I am writing a lot of data to a file, and while keeping my eye on the file it eventually stopped growing in size. Essentially my task is getting information from a database, and printing out all non-unique values in column A. Since there are many rows to the database table, and the database table is across my network, this is taking days to complete. Thus I'm concerned that since the file isn't growing, that it isn't actually writing to the file anymore. Which is odd, I have no "catch"'s in my code, so if there was a problem writing to file, wouldn't it have thrown an error?! Should I let the task complete (estimate 2-3 days from today), or is there something else that I don't know going on here making my application not write to the file?! my algorithm goes something like this Declare file Create new file Open file for writing get database connection get resultset from database for each row in the resultset - write column "A" to file - if row# % 100000 then write to screen "completed " + row# + " rows" when no more rows exist close file write to screen - "completed"

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• How to determine ASP.NET's generated ID's from codebehind?

  - by Matthew Scharley

  In ASP.NET, when you give a tag an ID it generates a unique HTML id for the element based on the control hierachy, ie. <asp:Panel ID="test" runat="server"> ... </asp:Panel> <!-- Becomes... --> <div id="plc_lt_zoneContent_PagePlaceholder_PagePlaceholder_lt_test_test"> ... </div> Is there some way of determining the generated id in the codebehind file? I need to generate some Javascript that uses the id.

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• Setting id to a panel control in gridview

  - by mariki

  I have a panel control in gridview's template. I need to hide/unhide panel in javascript function, for that i need to pass panel's id to the javascript. The problem is that all panels have the same id in gridview, so I need to set unique id to each panel. I tried to do: <asp:Panel id= "Panel_<%# Eval("ID")%>" and some other variations but always get an error. The panel contains some other controls, I need it to be server side because I need to set at code-behind (after checking if user is authenticated) What can I do? p.s. It doesn't have to be Panel, any other control that I can find with Findcontrol and can hold other controls.

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• Hibernate Auto-Increment not working

  - by dharga

  I have a column in my DB that is set with Identity(1,1) and I can't get hibernate annotations to work for it. I get errors when I try to create a new record. In my entity I have the following. @GeneratedValue(strategy=GenerationType.IDENTITY, generator="native") @Column(name="SeqNo", unique=true, nullable=false) BigDecimal seqNo; But when I try to add a new record I get the following error. Cannot insert explicit value for identity column in table 'MemberSelectedOptions' when IDENTITY_INSERT is set to OFF. I don't want to set IDENTIY_INSERT to ON because I want the identity column in the db to manage the values. The SQL that is run is the following; where you can clearly see the insert. insert into dbo.MemberSelectedOptions (OptionStatusCd, EffectiveDate, TermDate, SelectionStatusDate, SysLstUpdtUserId, SysLstTrxDtm, SourceApplication, GroupId, MemberId, OptionId, SeqNo) values (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?) What am I missing?

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• Using css "active tab" technique on single page

  - by flash

  I'm building a navigation system using jquery scrollto. I have my navigation menu in a separate file (( navigation.php )). It is included in 5 locations on the first page (( 5 different sections w/ text following each )). I'm trying to figure out a way to have the current "tab" highlight'd. I could hard code the navigation in each location to ensure it shows up the correct way, but I'd rather use the phpinclude() method. The other issue is that each "tab" has it's own unique color (( cmykd )). Here is the alpha version of what I'm doing (( when you click && the page slides, the "active tab" still stays grey -- I'd like it to be the corresponding color )). Hope this all makes sense && thanks in advance !!

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• Filtering and then counting distinct values

  - by Deon

  This is for Excel: I've been tasked with counting distinct records after I have filtered the data. I have 330 rows with column A containing the 'name' and in Column B I have the name of a test that was done for each 'name', which each 'name' could have taken several iterations of the same test. The test results are in Column C. Col A -Student Col B -Exam Col C - Grade Student 1 Exam 1 .80 Student 2 Exam 1 .50 Student 3 Exam 1 .90 Student 2 Exam 1 .75 Student 4 Exam 1 .90 Student 5 Exam 1 .55 Student 2 Exam 2 .90 Student 1 Exam 2 .90 .... .... ... If I filter col B for Exam 1, I want to count the unique number of students that have taken Exam 1.

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• Batch processing JDBC

  - by Wai Hein

  I am practicing JDBC batch processing and having errors: error 1: Unsupported feature error 2: Execute cannot be empty or null Property files include: itemsdao.updateBookName = Update Books set bookname = ? where books.id = ? itemsdao.updateAuthorName = Update books set authorname = ? where books.id = ? I know I can execute about DML statements in one update, but I am practicing batch processing in JDBC. Below is my method public void update(Item item) { String query = null; try { connection = DbConnector.getConnection(); property = SqlPropertiesLoader.getProperties("dml.properties"); connection.setAutoCommit(false); if ( property == null ) { Logging.log.debug("dml.properties does not exist. Check property loader or file name is spelled right"); return; } query = property.getProperty("itemsdao.updateBookName"); statement = connection.prepareStatement(query); statement.setString(1, item.getBookName()); statement.setInt(2, item.getId()); statement.addBatch(query); query = property.getProperty("itemsdao.updateAuthorName"); statement = connection.prepareStatement(query); statement.setString(1, item.getAuthorName()); statement.setInt(2, item.getId()); statement.addBatch(query); statement.executeBatch(); connection.commit(); }catch (ClassNotFoundException e) { Logging.log.error("Connection class does not exist", e); } catch (SQLException e) { Logging.log.error("Violating PK constraint",e); } //helper class th finally { DbUtil.close(connection); DbUtil.closePreparedStatement(statement); }

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