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  • Need a cleaner way, which avoids too many 'if statements', to write this method for inputing data in

    - by indiehacker
    What is the best way to reference datastore model attributes without using the four 'if statements' I have in the below sample code, which seem messy and inefficient. For real-world code I may have a situation of 100 attributes such as self.var1, self.var2, ... self.varN that I want to some how reference with just an integer (or strings) as an argument to some method. class PixelObject(db.Model): zoom0 = db.ListProperty(int) zoom1 = db.ListProperty(int) zoom2 = db.ListProperty(int) zoom3 = db.ListProperty(int) zoom4 = db.ListProperty(int) def inputZoomData(self, zoomInteger, input_data): """input_data goes to specified attribute based on if 0,1,2,3,or 4 is argument""" if zoomInteger == 0: self.zoom0 = input_data if zoomInteger == 1: self.zoom1 = input_data if zoomInteger == 2: self.zoom2 = input_data if zoomInteger == 3: self.zoom3 = input_data if zoomInteger == 4: self.zoom4 = input_data

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  • Why is the Objective-C Boolean data type defined as a signed char?

    - by EddieCatflap
    Something that has piqued my interest is Objective-C's BOOL type definition. Why is it defined as a signed char (which could cause unexpected behaviour if a value greater than 1 byte in length is assigned to it) rather than as an int, as C does (much less margin for error: a zero value is false, a non-zero value is true)? The only reason I can think of is the Objective-C designers micro-optimising storage because the char will use less memory than the int. Please can someone enlighten me?

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  • How to pick random (small) data samples using Map/Reduce?

    - by Andrei Savu
    I want to write a map/reduce job to select a number of random samples from a large dataset based on a row level condition. I want to minimize the number of intermediate keys. Pseudocode: for each row if row matches condition put the row.id in the bucket if the bucket is not already large enough Have you done something like this? Is there any well known algorithm? A sample containing sequential rows is also good enough. Thanks.

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  • Use a foreign key mapping to get data from the other table using Python and SQLAlchemy.

    - by Az
    Hmm, the title was harder to formulate than I thought. Basically, I've got these simple classes mapped to tables, using SQLAlchemy. I know they're missing a few items but those aren't essential for highlighting the problem. class Customer(object): def __init__(self, uid, name, email): self.uid = uid self.name = name self.email = email def __repr__(self): return str(self) def __str__(self): return "Cust: %s, Name: %s (Email: %s)" %(self.uid, self.name, self.email) The above is basically a simple customer with an id, name and an email address. class Order(object): def __init__(self, item_id, item_name, customer): self.item_id = item_id self.item_name = item_name self.customer = None def __repr__(self): return str(self) def __str__(self): return "Item ID %s: %s, has been ordered by customer no. %s" %(self.item_id, self.item_name, self.customer) This is the Orders class that just holds the order information: an id, a name and a reference to a customer. It's initialised to None to indicate that this item doesn't have a customer yet. The code's job will assign the item a customer. The following code maps these classes to respective database tables. # SQLAlchemy database transmutation engine = create_engine('sqlite:///:memory:', echo=False) metadata = MetaData() customers_table = Table('customers', metadata, Column('uid', Integer, primary_key=True), Column('name', String), Column('email', String) ) orders_table = Table('orders', metadata, Column('item_id', Integer, primary_key=True), Column('item_name', String), Column('customer', Integer, ForeignKey('customers.uid')) ) metadata.create_all(engine) mapper(Customer, customers_table) mapper(Orders, orders_table) Now if I do something like: for order in session.query(Order): print order I can get a list of orders in this form: Item ID 1001: MX4000 Laser Mouse, has been ordered by customer no. 12 What I want to do is find out customer 12's name and email address (which is why I used the ForeignKey into the Customer table). How would I go about it?

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  • Ruby and jQuery -- $(document).ajaxSend() not modifying the params as expected

    - by Jason
    I cannot get jquery's ajaxSend (http://api.jquery.com/ajaxSend/) to properly modify the parameters. I have: $(document).ajaxSend(function(event, request, settings) { settings.data = $.deparam(settings.data); settings.data['random'] = new Date().getTime(); settings.data['_method'] = 'get'; settings.data = $.param(settings.data) $.log(settings); }); $(document).ready(function() { //...snip... $.ajaxSetup({ data : { remote : 1, authenticity_token : encodeURIComponent(AUTH_TOKEN) } }); }); The idea here is that we always want 4 param sent across: remote and auth_token always get set properly. However, random and _method (both needed for IE issues) do not get set. Logging settings inside ajaxSend shows me that they are set to settings.data: "remote=1&authenticity_token=6GA9R_snip_253D&random=1270584905846&_method=get" but when it gets sent across the wire, I only have the following: authenticity_token 6GA9R_snip_253D remote 1 Why in the world is this not working?

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  • How do you delete a pointer without deleting the data the pointer points to?

    - by Faken
    I have a pointer that points to an array and another pointer referencing the same array. How do i delete any one of those pointers without killing the array such that the second undeleted pointer still works? for example: int* pointer1 = new int [1000]; int* pointer2; pointer2 = pointer1; Now i want to get rid of pointer1, how would i do it such that i can continue to access the array normaly through pointer2?

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  • With PHP and AJAX, Can two clients inter-exchange data without MySQL?

    - by Devyn
    Hi, Let's assume I'm developing a AJAX, PHP chess game. During the game, one movement of a player will be notified to the another but we are not saving that information. Normally, we used to store in MySQL every time a player makes movement and show update position to another player. What I want is to reduce MySQL load as much as possible and server is not interested in movements between two players. Server will only save final result like who wins. So what should I do?

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  • Do Managers in Python Multiprocessing module lock the shared data?

    - by AnonProcess
    This Question has been asked before: http://stackoverflow.com/questions/2936626/how-to-share-a-dictionary-between-multiple-processes-in-python-without-locking However I have several doubts regarding the program given in the answer: The issue is that the following step isn't atomic d['blah'] += 1 Even with locking the answer provided in that question would lead to random results. Since Process 1 read value of d['blah'] saves it on the stack increments it and again writes it. In Between a Process 2 can read the d['blah'] as well. Locking means that while d['blah'] is being written or read no other process can access it. Can someone clarify my doubts?

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  • CodeIgniter Form Validation

    - by mmcglynn
    I am trying to set up validation on a simple contact form that is created using the form helper. No validation at all occurs. What is wrong? In the code below, the “good” keyword always shows, regardless of what is entered into the form, and the saved values set via set_value are never shown. Controller // Contact function contact() { $data['pageTitle'] = "Contact"; $data['bodyId'] = "contact"; $this->load->library('form_validation'); $config_rules = array ('email' => 'required','message' => 'required'); $this->form_validation->set_rules($config_rules); if ($this->form_validation->run() == FALSE) { echo "bad"; $data['include'] = "v_contact"; $this->load->view('v_template',$data); } else { echo "good"; $data['include'] = "v_contact"; $this->load->view('v_template',$data); } } View echo validation_errors(); echo form_open('events/contact'); // name echo form_label('Name', 'name'); $data = array ( 'name' => 'name', 'id' => 'name', 'maxlength' => '64', 'size' => '40', 'value' => set_value('name') ); echo form_input($data) . "\n<br />"; // email address echo form_label('Email Address', 'email'); $data = array ( 'name' => 'email', 'id' => 'email', 'maxlength' => '64', 'size' => '40', 'value' => set_value('email') ); echo form_input($data) . "\n<br />"; // message echo form_label('Message', 'message'); $data = array ( 'name' => 'message', 'id' => 'message', 'rows' => '8', 'cols' => '35', 'value' => set_value('message') ); echo form_textarea($data) . "\n<br />"; echo form_submit('mysubmit', 'Send Message'); echo form_close();

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  • Using SSIS, how do you read a datetime field into a variable that is of Data Type string?

    - by Mark Kadlec
    This one has bugged me for the longest time and a great question to ask the Stackoverflow users I think. I have a rather large SSIS flow that uses a string variable to store the datetime. I would now like to dynamically read the datetime value from the database, but how would you construct the SSIS to do this? My first obvious thought would be to simply execute a SQL task to get the datetime and store it in the variable, but got the "differs from the current variable type" error. Is there a simple way to convert the database datetime into a String variable? Any help from the community would be appreciated,

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  • How can I bind dynamic data to DataGridTemplateColun in code?

    - by TuomoT
    I'm using DataGrid from CodePlex. I have objects (ICustomTypeDescriptor) that have properties 'name' 'description' 'c' 'd' and so on (the names are dynamic, and so is the value) and they have information behind them. I have templates for different types. And if I have to list the properties of a single element I can just bind to the values in xaml and use datatemplateselector (in datagridtemplatecolumn) which will pick the correct template. However, when I'm listing several of the elements, how can I use the selectors and the templates? How do I get the correct property bound to the template (two-way)? When ignoring the need for different templates, using DataGridTextColumn with bindings is very simple (and works, see example below), is there any way to use similar approach with the DataGridTemplateColumn? foreach (String propertyName in listOfPropertyNames) { DataGridTextColumn textColumn = new DataGridTextColumn() { Header = propertyName, Binding = new Binding() { Path = new PropertyPath(propertyName) } }; DataGrid.Columns.Add(textColumn); }

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  • There has to be an easier way.. pulling data from mysql

    - by Daniel Hunter
    I need to pull 3 values from a table and assign each one to a variable each value is based on to columns, a type and an id $ht_live_query = mysql_query("SELECT htcode FROM coupon WHERE pid='$pid' AND type='L'"); $ht_live_result = mysql_fetch_array($ht_live_query); $htCODE_Live = $ht_live_result['htcode']; You can see that I am assigning the desired value to the variable $htL $ht_General_query = mysql_query("SELECT htcode FROM coupon WHERE pid='$pid' AND type='G'"); $ht_General_result = mysql_fetch_array($ht_General_query); $htCODE_General = $ht_General_result['htcode']; $ht_Reward_query = mysql_query("SELECT htcode FROM coupon WHERE pid='$pid' AND type='R'"); $ht_Reward_result = mysql_fetch_array($ht_Reward_query); $htCODE_Reward = $ht_Reward_result ['htcode']; I know I am doing this the hard way but can not figure out how to do the foreach or while loop to attain the desired results.

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  • How to alter Postgres table data based on its contents?

    - by williamjones
    This is probably a super simple question, but I'm struggling to come up with the right keywords to find it on Google. I have a Postgres table that has among its contents a column of type text named content_type. That stores what type of entry is stored in that row. There are only about 5 different types, and I decided I want to change one of them to display as something else in my application (I had been directly displaying these). It struck me that it's funny that my view is being dictated by my database model, and I decided I would convert the types being stored in my database as strings into integers, and enumerate the possible types in my application with constants that convert them into their display names. That way, if I ever got the urge to change any category names again, I could just change it with one alteration of a constant. I also have the hunch that storing integers might be somewhat more efficient than storing text in the database. First, a quick threshold question of, is this a good idea? Any feedback or anything I missed? Second, and my main question, what's the Postgres command I could enter to make an alteration like this? I'm thinking I could start by renaming the old content_type column to old_content_type and then creating a new integer column content_type. However, what command would look at a row's old_content_type and fill in the new content_type column based off of that?

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  • Io exception: There is no process to read data written to a pipe.

    - by Srikanth
    I'm using Hibernate3.2+Websphere6.0+struts1.3.. After deploying ,application works fine. After some idle time ,i will get this type of error repeatedly,am not able to login at all. Im not using any connection pooling. i feel after idle time its not able to connect to the database again..if i restart the server everything works fine for some time...after that same story.. please help me out

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  • How to set HTML list as mx:DataGrid data provider?

    - by Ole Jak
    So I have Html like this http://trac.edgewall.org/wiki/RecentChanges (I want to create some Flash Track reader which will be opensource) I need to list in my DataGrid Index of all viki pages in form like +-----------+--------+ |page name |page url| +-----------+--------+ | name | url | +-----------+--------+

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  • Multi Player game using Nodejs and Socket IO

    - by Kishorevarma
    I am trying out multi player racing game using Node and Socket IO ,express . So I have tried simple example to see the latency between node server and the clients. I have a draggable image in client . when I move the image ienter code heren one client ,it has to move in all clients. so basically when I am moving the image I am sending the image position to the node server in a json format , then from there I am broadcasting to all clients. there is a ~approx 300ms latency from the time. following are the results. Client 1 sending data to server at : 286136 (timestamp) Server received at : 286271 Client2 received data at : 286470 Client3 received data at : 286479 Client4 received data at : 286487 Client5 received data at : 286520 the latency between move from client1 to client5 is 384ms. its too hight for a racing game .. here is my server code. var app = require('express').createServer(); var io = require('socket.io'); var http = require('http'); var http_server = http.createServer(); var server = http.createServer(app); server.listen(3000); var socket = io.listen(server,{ log: false }); socket.sockets.on('connection', function (client) { client.on('message', function (data){ console.log("data arrived to server",new Date().getTime()); // Below both statements are giving same latency between the client 1 and client 5 client.broadcast.emit('message',data); //socket.sockets.emit('message',data); }); }); 1) Is there any way to optimize the server code to reduce the latency? 2) is this expected latency using node and websockets ? 3) is socket io can't broadcast the data asynchronously (I mean at a same time) ? Thanks Kishorevarma

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  • How can I store large amount of data from a database to XML (speed problem, part three)?

    - by Andrija
    After getting some responses, the current situation is that I'm using this tip: http://www.ibm.com/developerworks/xml/library/x-tipbigdoc5.html (Listing 1. Turning ResultSets into XML), and XMLWriter for Java from http://www.megginson.com/downloads/ . Basically, it reads date from the database and writes them to a file as characters, using column names to create opening and closing tags. While doing so, I need to make two changes to the input stream, namely to the dates and numbers. // Iterate over the set while (rs.next()) { w.startElement("row"); for (int i = 0; i < count; i++) { Object ob = rs.getObject(i + 1); if (rs.wasNull()) { ob = null; } String colName = meta.getColumnLabel(i + 1); if (ob != null ) { if (ob instanceof Timestamp) { w.dataElement(colName, Util.formatDate((Timestamp)ob, dateFormat)); } else if (ob instanceof BigDecimal){ w.dataElement(colName, Util.transformToHTML(new Integer(((BigDecimal)ob).intValue()))); } else { w.dataElement(colName, ob.toString()); } } else { w.emptyElement(colName); } } w.endElement("row"); } The SQL that gets the results has the to_number command (e.g. to_number(sif.ID) ID ) and the to_date command (e.g. TO_DATE (sif.datum_do, 'DD.MM.RRRR') datum_do). The problems are that the returning date is a timestamp, meaning I don't get 14.02.2010 but rather 14.02.2010 00:00:000 so I have to format it to the dd.mm.yyyy format. The second problem are the numbers; for some reason, they are in database as varchar2 and can have leading zeroes that need to be stripped; I'm guessing I could do that in my SQL with the trim function so the Util.transformToHTML is unnecessary (for clarification, here's the method): public static String transformToHTML(Integer number) { String result = ""; try { result = number.toString(); } catch (Exception e) {} return result; } What I'd like to know is a) Can I get the date in the format I want and skip additional processing thus shortening the processing time? b) Is there a better way to do this? We're talking about XML files that are in the 50 MB - 250 MB filesize category.

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  • Objective C: Function returning correct data for the first time of call and null for other times

    - by Kooshal Bhungy
    Hi all, Am a beginner in objective C, i am implementing a function that would query a web server and display the returning string in console. I am calling the function (getDatafromServer) repeatedly in a loop. The problem is that the first time am getting the value whereas the other times, it returns me a (null) in console... I've searched about memory management and check out on the forums but none have worked. Can you please guys tell me where am wrong in the codes below? Thanks in advance.... @implementation RequestThread +(void)startthread:(id)param{ while (true) { //NSLog(@"Test threads"); sleep(5); NSLog(@"%@",[self getDatafromServer]); } } +(NSString *) getDatafromServer{ NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init]; NSString *myRequestString = @"name=Hello%20&[email protected]"; NSData *myRequestData = [NSData dataWithBytes:[myRequestString UTF8String] length:[myRequestString length]]; NSMutableURLRequest *request = [[NSMutableURLRequest alloc] initWithURL: [NSURL URLWithString:@"http://192.168.1.32/gs/includes/widget/getcalls.php?user=asdasd&passw=asdasdasd"]]; [request setHTTPMethod:@"POST"]; [request setHTTPBody: myRequestData]; [request setValue:@"application/x-www-form-urlencoded" forHTTPHeaderField:@"content-type"]; NSData *returnData = [NSURLConnection sendSynchronousRequest:request returningResponse:nil error:nil]; NSString *myString = [NSString stringWithUTF8String:[returnData bytes]]; [myRequestString release]; [request release]; [returnData release]; return myString; [pool release]; } @end

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