Search Results

Search found 89926 results on 3598 pages for 'abstract data type'.

Page 582/3598 | < Previous Page | 578 579 580 581 582 583 584 585 586 587 588 589  | Next Page >

  • How do I sub sample data by group using ddply?

    - by Maiasaura
    I've got a data frame with far too many rows to be able to do a spatial correlogram. Instead, I want to grab 40 rows for each species and run my correlogram on that subset. I wrote a function to subset a data frame as follows: samp <- function(dataf) { dataf[sample(1:dim(dataf)[1], size=40, replace=FALSE),] } Now I want to apply this function to each species in a larger data frame. When I try something like culled_data = ddply (larger_data, .(species), subset, samp) I get this error: Error in subset.data.frame(piece, ...) : 'subset' must evaluate to logical Anyone got ideas on how to do this?

    Read the article

  • I serialized a C++ object, how to allocate memory for it without knowing what type it is?

    - by Neo_b
    Hello, I have serialized a C++ object and I wish to allocate space for it, although I can't use the "new" operator, because I do not know the object's class. I tried using malloc(sizeof(object)), although trying to typecast the pointer to the type the serialized object is of, the program shut down. Where is the information about the object class stored? class object { public: virtual void somefunc(); int someint; }; class objectchild:public object { } object *o=(object*)malloc(sizeof(objectchild)); cout << int(dynamic_cast<objectchild*>(o)) << endl; This causes a program shutdown. Thank you in advance.

    Read the article

  • How to handle added input data colums without having to maintain multiple versions of SSIS packages?

    - by GLFelger
    I’m writing to solicit ideas for a solution to an upcoming problem. The product that provides data to our ETL process currently has multiple versions. Our clients are all using some version of the product, but not all use the same version and they will not all be upgraded at the same time. As new versions of the product are rolled out, the most common change is to add new data columns. Columns being dropped or renamed may happen occasionally, but our main focus right now is how to handle new columns being added. The problem that we want to address is how to handle the data for clients who use an older version of the product. If we don’t account for the new columns in our SSIS packages, then the data in those columns for clients using an older product version will not be processed. What we want to avoid is having to maintain a separate version of the SSIS packages for each version of the product. Has anyone successfully implemented a solution for this situation?

    Read the article

  • In a C++ template, is it allowed to return an object with spesific type parameters?

    - by nieldw
    When I've got a template with certain type parameters, is it allowed for a function to return an object of this same template, but with different types? In other words, is the following allowed? template<class edgeDecor, class vertexDecor, bool dir> Graph<edgeDecor,int,dir> Graph<edgeDecor,vertexDecor,dir>::Dijkstra(vertex s, bool print = false) const { /* Construct new Graph with apropriate decorators */ Graph<edgeDecor,int,dir> span = new Graph<edgeDecor,int,dir>(); /* ... */ return span; }; If this is not allowed, how can I accomplish the same kind of thing?

    Read the article

  • Without using PECL or system() type functions, is there a way to look up DNS records using PHP?

    - by Navarr
    I'm working on creating a new type of email protocol, and in order to do that I had to set up an SRV DNS record for my domain. In promoting this protocol, I'll need to be able to discover if a given host uses my system (and if not fall back to an older protocol). So, is there a way to pull a DNS record (such as SRV) using PHP without using a PECL extension or running it through the linux command line (I already know I can ob_start() and system("host -t SRV hostname") but I'm looking for a better way, if it exists.)

    Read the article

  • Can I have a type that's both, covariant and contravariant, i.e. fully fungible/changeable with sub

    - by Water Cooler v2
    Just a stupid question. I could try it out in 2 minutes, really. It's just that I have 1 GB RAM and have already got 2 instances of VS 2010 open on my desktop, with an instance of VS 2005, too. Opening another instance of VS 2010 would be an over kill. Can I have a type (for now forgetting its semantics) that can be covariant as well as contravariant? For e.g. public interface Foo<in out T> { void DoFooWith(T arg); } Off to Eric Lippert's blog for the meat and potatoes of variance in C# 4.0 as there's little else anywhere that covers adequate ground on the subject.

    Read the article

  • Annotation based data structure visualization - are there similar tools out there?

    - by Helper Method
    For a project at university I plan to build an annotation based tool to visualize/play around with data structures. Here's my idea: Students which want to try out their self-written data structures need to: mark the type of their data structures using some sort of marker annotation e.g. @List public class MyList { ... } so that I know how to represent the data structure need to provide an iterator so that I can retrieve the elements in the right order need to annotate methods for insertion and removal, e.g. @add public boolean insert(E e) { ... } so that I can "bind" that method to some button. Do similar applications exist? I googled a little bit around but didn't find anything like that.

    Read the article

  • in actionscript, how to tell whether the type of a number if Number or int or uint?

    - by ty
    var n:Number = 1; trace("n is Number:" + (n is Number)); //true trace("n is int:" + (n is int)); //true trace("n is uint:" + (n is uint)); //true var m:Number = 1; trace("m is Number:" + (m is Number)); //true trace("m is int:" + (m is int)); //true trace("m is uint:" + (m is uint)); //true They all true! in actionscript, how to tell whether the type of a number if Number or int or uint?

    Read the article

  • PHP - get MySQL query results as their native data type?

    - by redidas
    I've tried fetching MySQL query results using mysql_fetch_row() mysql_result() and numeric values are being returned as strings. Is there any way to fetch the data as its datatype stored in the table? The application will be querying many different queries so I will be unable to cast the values as the intended datatype on a 1 by 1 basis.

    Read the article

  • how can i display the database data to an jtable(dynamic) in the swings!

    - by harish0510
    we are using hibernate in business layer,but the task is, by using the jtable in swings to display the dynamic data(swings) from the database. code: Criteria criteria=session.createCriteria(User.class); //here user.class is pojo class in hibernate. List studentlist= criteria.list(); System.out.println("records"+studentlist); here the data is showing in hibernate console, but how to represent that data in the format of "jtable".

    Read the article

  • Use SQL to clone data in two tables that have a 1-1 relationship with each other

    - by AmoebaMan17
    Using MS SQL 2005, Table 1 ID | T1Value | T2ID | GroupID ---------------------------------- 1 | a | 10 | 1 2 | b | 11 | 1 3 | c | 12 | 1 4 | a | 22 | 2 Table 2 ID | T2Value ---------------- 10 | H 11 | J 12 | K 22 | H I want to clone the data for GroupID == 1 into a new GroupID so that I result with the following: Table 1 ID | T1Value | T2ID | GroupID ---------------------------------- 1 | a | 10 | 1 2 | b | 11 | 1 3 | c | 12 | 1 4 | a | 22 | 2 5 | a | 23 | 3 6 | b | 24 | 3 7 | c | 25 | 3 Table 2 ID | T2Value ---------------- 10 | H 11 | J 12 | K 22 | H 23 | H 24 | J 25 | K I've found some SQL clone patterns that allow me to clone data in the same table well... but as I start to deal with cloning data in two tables at the same time and then linking up the new rows correctly... that's just not something I feel like I have a good grasp of. I thought I could do some self-joins to deal with this, but I am worried in the cases where the non-key fields have the same data in multiple rows.

    Read the article

  • Which code snipplets in PHP can create a input form, which creates a new set of data in my mysql dat

    - by smiyazaki
    I am using the Google Maps API with parts in javascript and others in PHP. <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"> Google Maps AJAX + mySQL/PHP Example // var iconBlue = new GIcon(); iconBlue.image = 'icon.png'; iconBlue.shadow = ''; iconBlue.iconSize = new GSize(19, 19); iconBlue.shadowSize = new GSize(22, 20); iconBlue.iconAnchor = new GPoint(6, 20); iconBlue.infoWindowAnchor = new GPoint(5, 1); var iconRed = new GIcon(); iconRed.image = 'icon.png'; iconRed.shadow = ''; iconRed.iconSize = new GSize(19, 19); iconRed.shadowSize = new GSize(22, 20); iconRed.iconAnchor = new GPoint(6, 20); iconRed.infoWindowAnchor = new GPoint(5, 1); var customIcons = []; customIcons["restaurant"] = iconBlue; customIcons["bar"] = iconRed; function load() { if (GBrowserIsCompatible()) { var map = new GMap2(document.getElementById("map")); map.setMapType(G_SATELLITE_MAP); map.addControl(new GSmallMapControl()); map.addControl(new GMapTypeControl()); map.setCenter(new GLatLng(47.614495, -122.341861), 13); // Change this depending on the name of your PHP file GDownloadUrl("phpsqlajax_genxml.php", function(data) { var xml = GXml.parse(data); var markers = xml.documentElement.getElementsByTagName("marker"); for (var i = 0; i < markers.length; i++) { var name = markers[i].getAttribute("name"); var address = markers[i].getAttribute("address"); var type = markers[i].getAttribute("type"); var point = new GLatLng(parseFloat(markers[i].getAttribute("lat")), parseFloat(markers[i].getAttribute("lng"))); var marker = createMarker(point, name, address, type); map.addOverlay(marker); } }); } } function createMarker(point, name, address, type) { var marker = new GMarker(point, customIcons[type]); var html = "<b>" + name + "</b> <br/>" + address; GEvent.addListener(marker, 'click', function() { marker.openInfoWindowHtml(html); }); return marker; } //]]> (I suppose the php will be called by "GDownloadUrl("phpsqlajax_genxml.php", function(data) { ..." in the javascript part of the sourcecode of phpsqlajax_map.htm) Now I need another php file and the code snipplets for it, which creates an input form where I can add some new locations to the google map. Following code is used to create the xml file here: http://detektors.de/maptest/phpsqlajax_genxml.php The next step would be, trying to make an plugin for wordpress that I could easily post a blog entry with a new location on the same map, which displays already some other locations stored in the mysql database. thanks! <?php require("phpsqlajax_dbinfo.php"); function parseToXML($htmlStr) { $xmlStr=str_replace('<','<',$htmlStr); $xmlStr=str_replace('','>',$xmlStr); $xmlStr=str_replace('"','"',$xmlStr); $xmlStr=str_replace("'",''',$xmlStr); $xmlStr=str_replace("&",'&',$xmlStr); return $xmlStr; } // Opens a connection to a MySQL server $connection=mysql_connect ($host, $username, $password); if (!$connection) { die('Not connected : ' . mysql_error()); } // Set the active MySQL database $db_selected = mysql_select_db($database, $connection); if (!$db_selected) { die ('Can\'t use db : ' . mysql_error()); } // Select all the rows in the markers table $query = "SELECT * FROM markers WHERE 1"; $result = mysql_query($query); if (!$result) { die('Invalid query: ' . mysql_error()); } header("Content-type: text/xml"); // Start XML file, echo parent node echo ''; // Iterate through the rows, printing XML nodes for each while ($row = @mysql_fetch_assoc($result)){ // ADD TO XML DOCUMENT NODE echo ''; } // End XML file echo ''; ?

    Read the article

  • Cast A primitive type pointer to A structure pointer - Alignment and Padding?

    - by Seçkin Savasçi
    Just 20 minutes age when I answered a question, I come up with an interesting scenario that I'm not sure of the behavior: Let me have an integer array of size n, pointed by intPtr; int* intPtr; and let me also have a struct like this: typedef struct { int val1; int val2; //and less or more integer declarations goes on like this(not any other type) }intStruct; My question is if I do a cast intStruct* structPtr = (intStruct*) intPtr; Am I sure to get every element correctly if I traverse the elements of the struct? Is there any possibility of miss-alignment(possible because of padding) in any architecture/compiler?

    Read the article

  • What's a good way to have sample data on the iPhone/iPad?

    - by MikeN
    I have an iPad application that pulls in all of its data from an external web service. I am working on building in a demo mode that will use a cache of demo data stored on the device so it can be demoed and tried out without the web service connection (or an internet connection.) Is there a project or good practices standard to follow to model this type of sample data? I'm expecting JSON arrays/Dictionaries back from my web service, how could I build a function that uses hardcoded data to create the NSMutableData object I'd expect to get back from a JSON web request?

    Read the article

  • Error about TypeError (wrong argument type Module (expected Class)): app/controllers/player_profiles_controller.rb:1:in `<top (required)>'

    - by edi susanto
    hy guys . . im new at this . . sorry for the word that's not understandable and the easy question . . i'd like to ask about an error that shown below : TypeError (wrong argument type Module (expected Class)): app/controllers/player_profiles_controller.rb:1:in `' i want to test the result by render json in soapUI. does anyone know what's the problem so that the error will show up like above ? thanks before.regards,edy

    Read the article

  • enable_shared_from_this and inheritance

    - by DeadMG
    I've got a type which inherits from enable_shared_from_this<type>, and another type that inherits from this type. Now I can't use the shared_from_this method because it returns the base type and in a specific derived class method I need the derived type. Is it valid to just construct a shared_ptr from this directly? Edit: In a related question, how can I move from an rvalue of type shared_ptr<base> to a type of shared_ptr<derived>? I used dynamic_cast to verify that it really was the correct type, but now I can't seem to accomplish the actual move.

    Read the article

  • How to change particular column entries in a mysql table when uploading data from csv file?

    - by understack
    I upload data into a mysql table from csv file in a standard way like this: TRUNCATE TABLE table_name; load data local infile '/path/to/file/file_name.csv' into table table_name fields terminated by ',' enclosed by '"' lines terminated by '\r\n' (id, name, type, deleted); All 'deleted' column entries in csv file has either 'current' or 'deleted' value. Question: When csv data is being loaded into table, I want to put current date in table for all those corresponding 'deleted' entries in csv file. And null for 'current' entries. How can I do this? Example: csv file: id_1, name_1, type_1, current id_2, name_1, type_2, deleted id_3, name_3, type_3, current Table after loading this data should look like this: id_1, name_1, type_1, null id_2, name_1, type_2, 2010-05-10 id_3, name_3, type_3, null Edit Probably, I could run another separate query after loading csv file. Wondering if it could be done in same query?

    Read the article

  • For LinqToSQL is 0 true or is 1 (for type Bit)?

    - by Vaccano
    I have a column of type Bit (called BBoolVal in this example). I have a LinqToSQL Statement Like this: var query = List<MyClass> myList = _ctx.DBList .Where(x => x.AGuidID == paramID) .Where(x => x.BBoolVal == false); When I look at the sql it ends up like this (I added the spacing and changed the names): SELECT [t0].[Id], [t0].[AGuidID], [t0].[OtherIDID], [t0].[TimeColumn], [t0].[BBoolVal], [t0].[MoreID] FROM [dbo].[MyTable] AS [t0] WHERE (NOT ([t0].[BBoolVal] = 1)) AND ([t0].[AGuidID] = @p0) Because my x.BBoolVal == false translates to [BBoolVal] == 1 I gather that false = 1 (and thus true = 0). I am asking because this seems a bit backwards to me. I am fine to accept it, I just want to be sure.

    Read the article

  • Use SQL to clone data in two tables that have a 1-1 relationship in each table

    - by AmoebaMan17
    Using MS SQL 2005, Table 1 ID | T1Value | T2ID | GroupID ---------------------------------- 1 | a | 10 | 1 2 | b | 11 | 1 3 | c | 12 | 1 4 | a | 22 | 2 Table 2 ID | T2Value ---------------- 10 | H 11 | J 12 | K 22 | H I want to clone the data for GroupID == 1 into a new GroupID so that I result with the following: Table 1 ID | T1Value | T2ID | GroupID ---------------------------------- 1 | a | 10 | 1 2 | b | 11 | 1 3 | c | 12 | 1 4 | a | 22 | 2 5 | a | 23 | 3 6 | b | 24 | 3 7 | c | 25 | 3 Table 2 ID | T2Value ---------------- 10 | H 11 | J 12 | K 22 | H 23 | H 24 | J 25 | K I've found some SQL clone patterns that allow me to clone data in the same table well... but as I start to deal with cloning data in two tables at the same time and then linking up the new rows correctly... that's just not something I feel like I have a good grasp of. I thought I could do some self-joins to deal with this, but I am worried in the cases where the non-key fields have the same data in multiple rows.

    Read the article

  • In a C++ template, is it allowed to return an object with specific type parameters?

    - by nieldw
    When I've got a template with certain type parameters, is it allowed for a function to return an object of this same template, but with different types? In other words, is the following allowed? template<class edgeDecor, class vertexDecor, bool dir> Graph<edgeDecor,int,dir> Graph<edgeDecor,vertexDecor,dir>::Dijkstra(vertex s, bool print = false) const { /* Construct new Graph with apropriate decorators */ Graph<edgeDecor,int,dir> span = new Graph<edgeDecor,int,dir>(); /* ... */ return span; }; If this is not allowed, how can I accomplish the same kind of thing?

    Read the article

  • how do i detect \r\n in a u_char type of buffer?

    - by aDi Adam
    i am trying to construct http content from packet sniffing in C. right now i am able to save all the packets in a file but i want to get rid of the headers in the first packet. they are also being saved as per they are a part of tcp payload. the actual body after the header starts after double "crlf" or \r\n\r\n in http response. how do i detect \r\n so that i can only save the following part of the buffer in the file. the buffer is u_char type. i cant figure out the command or the part i looked on google and other places but i mostly find c# commands, nothing in C.

    Read the article

< Previous Page | 578 579 580 581 582 583 584 585 586 587 588 589  | Next Page >