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• Does a HashMap retain the order of its elements on the next read if it is constructed as a LinkedHas

  - by javanix

  Suppose I have a Java method that returns a HashMap object. Because a LinkedHashMap is a subclass of HashMap, I can return a LinkedHashMap from this method just fine. On the next "read" action (no adding/removing/modifying of K/V pairs), would iterating over the keys of the resulting method (which returns a HashMap) go in the same order as the originating LinkedHashMap, even though the HashMap lacks the key links?

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• Turning A Stacked List into workable data

  - by BoSox

  In Excel I have a list of names that in the cell appear stacked, and I want each name in its own column. I was thinking Python may be a good way to do this? Example: Joe Smith John Hawk Mike Green Lauren Smith One cell will look exactly like that, with each name on its line within the cell but all of the names contained in the cell. I have 50 cells each with 1-20 stacked names and I want to put each name in its own cell on a given row. So, in my example all of those names would occupy the same row but each would have their own column. Any ideas?

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• What is the right data type for calculations in Java

  - by Raju

  Should we use double or BigDecimal for calculations in Java? How much is the overhead in terms of performance for BigDecimal as compared to double?

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• ASP.NET data bind two-way, bi-directional from code behind

  - by Konrad

  Hello, so for two-way (bi-directional) databinding in ASP, we do this... <asp:textbox id="txtField" runat="server" text='<%# Bind("SomeField") %>'> </asp:textbox> SomeField is located on the DataSource of the DetailsView that serves as the container for the textbox. Alternatively I could do this from code-behind (using the textbox's OnDataBinding event): protected void SomeField_OnDataBinding(object sender, EventArgs e) { ((TextBox)sender).Text = Eval("SomeField").ToString(); } However, EVAL is read-only...how can I specify Bind (two-way) from code-behind?

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• Accessing PostGIS spatial data from Rails

  - by Lakitu

  I need to use an existing PostGIS database from my Rails application. So far I am able to access the DB just fine, GeoRuby nicely converts the 'geom' column into a Point object. What I am looking for is an easy way to execute ActiveRecord-like queries on those tables, e.g. Poi.find_within_radius(...) or similar spatial queries like distance calculations et. al. I tried several combinations of geokit, accompanying rails plugins but I'm quite sure there must be something better out there in the ruby/rails universe. Any hints?

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• predicate subquery to return items by matching tags

  - by user3411663

  I have a many-to-many relationship between two entities; Item and Tag. I'm trying to create a predicate to take the selectedItem and return a ranking of items based on how many similar tags they have. So far I've tried: NSPredicate *predicate = [NSPredicate predicateWithFormat:@"SUBQUERY(itemToTag, $item, $item in %@).@count > 0", selectedItem.itemToTag]; Any other iterations that have failed. It currently only returns the selectedItem in the list. I've found little on Subquery. Is there a guru out there that can help me refine this? Thanks in advance for the help!

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• retrieve comma delimited data from a field in using SQL

  - by Nichols

  I've created a form in php that collects basic information. I have a list box that allows multiple items selected (ie housing, rent, food, water). If multiple items are selected they are stored in a field called Needs seperated by a comma. I have created a report ordered by the persons needs. The people who only have one need are sorted correctly, but the people who have multiple are sorted exactly as the string passed to the database (ie. housing, rent, food, water) -- which is not what i want. Is there a way to seperate the multiple values in this field using SQL to count each need instance/occurance as 1 so that there are no comma delimitations shown in the results? CLICK FOR EXAMPLE

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• Most efficient way to save tile data of an isometric game

  - by Harmen

  Hello, I'm working on an isometric game for fast browsers that support <canvas>, which is great fun. To save information of each tile, I use a two-dimensional array which contains numbers representing a tile ID, like: var level = [[1, 1, 1, 2, 1, 0], [0, 1, 1, 2, 0, 1], [0, 1, 1, 2, 1, 1]]; var tiles = [ {name: 'grass', color: 'green'}, {name: 'water', color: 'blue'}, {name: 'forest', color: 'ForestGreen'} ]; So far it works great, but now I want to work with heights and slopes like in this picture: For each tile I need to save it's tile ID, height and information about which corners are turned upward. I came up with a simple idea about a bitwise representation of all four corners, like this: 1011 // top, bottom and left corner turned up My question is: what is the most efficient way to save these three values for each cell? Is it possible to save these three values as one integer?

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• Is there a module that implements an efficient array type in Erlang?

  - by dsmith

  I have been looking for an array type with the following characteristics in Erlang. append(vector(), term()) O(1) nth(Idx, vector()) O(1) set(Idx, vector(), term()) O(1) insert(Idx, vector(), term()) O(N) remove(Idx, vector()) O(N) I normally use a tuple for this purpose, but the performance characteristics are not what I would want for large N. My testing shows the following performance characteristics... erlang:append_element/2 O(N). erlang:setelement/3 O(N). I have started on a module based on the clojure.lang.PersistentVector implementation, but if it's already been done I won't reinvent the wheel.

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• What is a flexible, hybrid python collection object?

  - by Naveen

  As a way to get used to python, I am trying to translate some of my code to python from Autohotkey_L. I am immediately running into tons of choices for collection objects. Can you help me figure out a built in type or a 3rd party contributed type that has as much as possible, the functionality of the AutoHotkey_L object type and its methods. AutoHotkey_L Objects have features of a python dict, list, and a class instance. I understand that there are tradeoffs for space and speed, but I am just interested in functionality rather than optimization issues.

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• NSEntityDescription entityForName returning nil

  - by Kamchatka

  Hi, I did some changes to my model (but I don't want migration yet, so I just remove the application, built clean etc.) so my application works in the simulator. However, when I run it on the iPhone, I get the following error: *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: 'executeFetchRequest:error: A fetch request must have an entity.' I set the entity like this: NSEntityDescription *entity = [NSEntityDescription entityForName:@"Document" inManagedObjectContext:managedObjectContext]; My managedObjectContext is not nil. But I suspect that it doesn't load the object model correctly or something similar because If I display the entities in the model, the list is empty. How can I make sure the model is loaded? Thanks,

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• Can't wrap my head around appengine data store persistence

  - by aloo

  Hi, I've run into the "can't operate on multiple entity groups in a single transaction." problem when using APPENGINE FOR JAVA w/ JDO with the following code: PersistenceManager pm = PMF.get().getPersistenceManager(); Query q = pm.newQuery("SELECT this FROM " + TypeA.class.getName() + " WHERE userId == userIdParam "); q.declareParameters("String userIdParam"); List<TypeA> poos = (List<TypeA>) q.execute(userIdParam); for (TypeA a : allTypeAs) { a.setSomeField(someValue); } pm.close(); } The problem it seems is that I can't operate on a multiple entities at the same time b/c they arent in the same entity group while in a transaction. Even though it doesn't seem like I'm in a transaction, appengine generates one because I have the following set in my jdoconfig.xml: <property name="datanucleus.appengine.autoCreateDatastoreTxns" value="true"/> Fine. So far I think I understand. BUT - if I replace TypeA in the above code, with TypeB - I don't get the error. I don't believe there is anything different between type a and type b - they both have the same key structure. They do have different fields but that shouldn't matter, right? My question is - what could possible be different between TypeA and TypeB that they give this different behavior? And consequently what do you I fundamentally misunderstand that this behavior could even exist.... Thanks.

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• ext-js data associate

  - by user121196

  can you associate a component or element in ext-js with a arbitrary object? eg. store(component, 'key', obj), get(component,'key');

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• IIS 7 Can't read data from ASP.Net application services tables

  - by vikp

  Hi, I'm working on deploying a web application written in C# with ASP.Net Application services databases. The application runs fine on the development machine. Windows Server 2003 has been built to test the application. The database has been scripted across using MS SQL Server GUI. ASP.Net application services tables were created using an utility. The connection strings are stored in the web.config and connectionStrings.config. The application connects to the database successfully, but then it times out after 10 seconds.

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• populatin jComBobox with data from a db tbl(table) column

  - by mnmyles

  Hi guyz? I have a JComboBox which i have named "venue_JCB" i want to load details from a tbl column on form load at the initcomponets() i have declared the method "accessDBinit() ;" and after the initComponets() i have implemented the accessDBinit(); method as follows: ================================code============================ void accessDBinit() //Get Student List in the List Box { try { sql = "SELECT classLevel FROM class_session ORDER BY classLevel"; java.lang.Class.forName("com.mysql.jdbc.Driver"); Connection con2=DriverManager.getConnection("jdbc:mysql:///coast","root",""); Statement stmt2 = (Statement)con2.createStatement(); boolean hasResults = stmt2.execute(sql); if(hasResults) { ResultSet rs2 = stmt2.getResultSet(); if(rs2!=null) { displayResultsinit(rs2); } db.stmt.close(); } } catch(Exception e) { System.out.println(e+"Error in connection"); } } void displayResultsinit(ResultSet r) throws SQLException { ResultSetMetaData rmeta = r.getMetaData(); int numColumns=rmeta.getColumnCount(); while(r.next()) { for(int i=1;i<=numColumns;++i) { if(i<=numColumns) { venue_JCB.addItem(r.getString(i)); } } } } ====================================end of code=================================== the method works (Populate the combobox) but at the output bar i get the following on form load and also whenever i select a component from the combobox ======= error===== java.lang.NullPointerExceptionError in connection could some one please tell me where i am going wrong with the method? Thanks in advance regards Malachi

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• Retrieving & Displaying data from csv files using AJAX

  - by JJ

  I need to provide a feature such that the user is able to upload a csv file.Once the uploading is done I need to retrieve each value and show it on a grid which is implemented using far point(http://www.fpoint.com/products/spread/spread.aspx).But all this has to be done without the page being refreshed.I use asp.net 2.0 & Ajax Pro.Remember I cannot use the inbuilt AJAX feature provided by microsoft .To be precise I need something similar to the lines of attaching a file using gmail. Thanks & Regards Bikram

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• Ember nested route. Load more models

  - by user3568719

  JsBin http://jsbin.com/EveQOke/153/ I know how to load more then one model to a route, using Ember.RSVP.hash. (see Jsbin Children menu). I use dynamic part to access one elem from a collection children/1. But i cant load more models to a nested resource. In my example i want to populate all the toys for a select, not just list the toys of the child. I have tried to access the model of the route children App.ChildRoute = Ember.Route.extend({ model: function(param){ return Ember.RSVP.hash({ allToys: this.modelFor("children"), child:this.store.find('child', param.child_id) }); } }); and use its model's toy property (since there have already loaded all of the toys) child.hbs <h4>All avaiable toys</h4> <table> {{#each toy in model.allToys.toys}} <tr> <td>{{toy.name}}</td> </tr> {{/each}} </table>

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• IQueryable and lazy loading

  - by Nelson

  I'm having a hard time determining the best way to handle this... With Entity Framework (and L2S), LINQ queries return IQueryable. I have read various opinions on whether the DAL/BLL should return IQueryable, IEnumerable or IList. Assuming we go with IList, then the query is run immediately and that control is not passed on to the next layer. This makes it easier to unit test, etc. You lose the ability to refine the query at higher levels, but you could simply create another method that allows you to refine the query and still return IList. And there are many more pros/cons. So far so good. Now comes Entity Framework and lazy loading. I am using POCO objects with proxies in .NET 4/VS 2010. In the presentation layer I do: foreach (Order order in bll.GetOrders()) { foreach (OrderLine orderLine in order.OrderLines) { // Do something } } In this case, GetOrders() returns IList so it executes immediately before returning to the PL. But in the next foreach, you have lazy loading which executes multiple SQL queries as it gets all the OrderLines. So basically, the PL is running SQL queries "on demand" in the wrong layer. Is there any sensible way to avoid this? I could turn lazy loading off, but then what's the point of having this "feature" that everyone was complaining EF1 didn't have? And I'll admit it is very useful in many scenarios. So I see several options: Somehow remove all associations in the entities and add methods to return them. This goes against the default EF behavior/code generation and makes it harder to do some composite (multiple entity) LINQ queries. It seems like a step backwards. I vote no. If we have lazy loading anyway which makes it hard to unit test, then go all the way and return IQueryable. You'll have more control farther up the layers. I still don't think this is a good option because IQueryable ties you to L2S, L2E, or your own full implementation of IQueryable. Lazy loading may run queries "on demand", but doesn't tie you to any specific interface. I vote no. Turn off lazy loading. You'll have to handle your associations manually. This could be with eager loading's .Include(). I vote yes in some specific cases. Keep IList and lazy loading. I vote yes in many cases, only due to the troubles with the others. Any other options or suggestions? I haven't found an option that really convinces me.

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• Unit Testing Model Classes that inherit from NSManagedObject

  - by Matt Baker

  So...I'm trying to get unit tests set up in my iPhone App but I'm having some issues. I'm trying to test my model classes but they inherit directly from NSManagedObject. I'm sure this is a problem but I don't know how to get around it. Everything is building and running as expected but I get this error when calling any method on the class I'm testing: Unknown.m:0:0 unrecognized selector sent to instance 0xc2b120 If I follow this structure (http://chanson.livejournal.com/115621.html) to create my object in my tests I end up with another error entirely but it still doesn't help me. Basically my question is this: how can I test a class that inherits from NSManagedObject?

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• using internationalization on list data

  - by singh

  i am using Struts2 in application. <s:iterator value="listObject"> <s:component template="abc.vm"> <s:param name="text" value="listValue" /> <s:param name="prefix" value="listIndex" /> </s:component> </s:iterator> listValue is a values of list. i am using iterator to traverse the list. now on listValue, i want to put here internationalization concept.so that all the list value can be display based on Locale which store in a list. please suggest!

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• How to convert a table column to another data type

  - by holden

  I have a column with the type of Varchar in my Postgres database which I meant to be integers... and now I want to change them, unfortunately this doesn't seem to work using my rails migration. change_column :table1, :columnB, :integer So I tried doing this: execute 'ALTER TABLE "table1" ALTER COLUMN "columnB" TYPE integer USING CAST(columnB AS INTEGER)' but cast doesn't work in this instance because some of the column are null... any ideas?

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• lock shared data using c#

  - by menacheb

  Hi, I have a program (C#) with a list of tests to do. Also, I have two thread. one to add task into the list, and one to read and remove from it the performed tasks. I'm using the 'lock' function each time one of the threads want to access to the list. Another thing I want to do is, if the list is empty, the thread who need to read from the list will sleep. and wake up when the first thread add a task to the list. Here is the code I wrote: ... List<String> myList = new List(); Thread writeThread, readThread; writeThread = new Thread(write); writeThread.Start(); readThraed = new Thread(read); readThread.Start(); ... private void write() { while(...) { ... lock(myList) { myList.Add(...); } ... if (!readThread.IsAlive) { readThraed = new Thread(read); readThread.Start(); } ... } ... } private void read() { bool noMoreTasks = false; while (!noMoreTasks) { lock (MyList)//syncronize with the ADD func. { if (dataFromClientList.Count > 0) { String task = myList.First(); myList.Remove(task); } else { noMoreTasks = true; } } ... } readThread.Abort(); } Apparently I did it wrong, and it's not performed as expected (The readTread does't read from the list). Does anyone know what is my problem, and how to make it right? Many thanks,

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• Decimal data Type Display scale part as zero

  - by Wael Dalloul

  I have Decimal field in SQLserver 2005 table, Price decimal(18, 4) if I write 12 it will be converted to 12.0000, if I write 12.33 it will be converted into 12.3300. Always it's putting zero to the right of the decimal point in the count of Scale Part(4). I was using these in SQL Server 2000, it was not behaving like this, in SQL Server 2000 if I put 12.5 it will be stored as 12.5 not as 12.5000 what SQLServer2005 do. My Question is how to stop SQL Server 2005 from putting zeros to the right of the decimal point?

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• How to direct people to fill out a form

  - by Solmead

  What is the best way to get people to fill out a form correctly? For instance I originally had a "Name" field on a form and I want 1 person per form. People filled it out like this: "Mark & Becky Newsman". So I broke it into 2 fields, "First Name" and "Last Name", And people are still filling it out wrong, like "First Name" = "Mark & Becky", "Last Name" = "Newsman". Are there any recommendations on how better to get people to understand that only one person's name should go there? I currently have it on two lines, would it work better to put both fields on one line? If this is on the wrong site go ahead and move it to the correct site.

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• python interactive web data/forms/interface communicating with remote server

  - by decipher

  What's an efficient method (preferably simple as well) for communicating with a remote server and allowing the user to 'interact' with it (IE submit commands, user interface) via the web browser (IE a text box to input commands, and an text area for output, or various command-less abstracted interfaces)? I have the 'standalone' python code finished for communicating and working(terminal/console based right now). My primary concern is with re-factoring the code to suite the web, which involves establishing a connection (python sockets), and maintaining the connection while the user is logged on. some further details: currently using django framework for the basic back end/templates.

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