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  • In Ruby, how does coerce() actually work?

    - by Jian Lin
    It is said that when we have a class Point and knows how to perform point * 3 like the following: class Point def initialize(x,y) @x, @y = x, y end def *(c) Point.new(@x * c, @y * c) end end point = Point.new(1,2) p point p point * 3 Output: #<Point:0x336094 @x=1, @y=2> #<Point:0x335fa4 @x=3, @y=6> but then, 3 * point is not understood: Point can't be coerced into Fixnum (TypeError) So we need to further define an instance method coerce: class Point def coerce(something) [self, something] end end p 3 * point Output: #<Point:0x3c45a88 @x=3, @y=6> So it is said that 3 * point is the same as 3.*(point) that is, the instance method * takes an argument point and invoke on the object 3. Now, since this method * doesn't know how to multiply a point, so point.coerce(3) will be called, and get back an array: [point, 3] and then * is once again applied to it, is that true? point * 3 which is the same as point.*(3) and now, this is understood and we now have a new Point object, as performed by the instance method * of the Point class. The question is: 1) who invokes point.coerce(3) ? Is it Ruby automatically, or is it some code inside of * method of Fixnum by catching an exception? Or is it by case statement that when it doesn't know one of the known types, then call coerce? 2) Does coerce always need to return an array of 2 elements? Can it be no array? Or can it be an array of 3 elements? 3) And is the rule that, the original operator (or method) * will then be invoked on element 0, with the argument of element 1? (element 0 and element 1 are the two elements in that array returned by coerce) Who does it? Is it done by Ruby or is it done by code in Fixnum? If it is done by code in Fixnum, then it is a "convention" that everybody follows when doing a coerce? So could it be the code in * of Fixnum do something like this: if (something.typeof? ...) else if ... # other type else if ... # other type else # if it is not a type I know array = something.coerce(self) return array[0].*(array[1]) end

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  • Creating .lib files in CUDA Toolkit 5

    - by user1683586
    I am taking my first faltering steps with CUDA Toolkit 5.0 RC using VS2010. Separate compilation has me confused. I tried to set up a project as a Static Library (.lib), but when I try to build it, it does not create a device-link.obj and I don't understand why. For instance, there are 2 files: A caller function that uses a function f #include "thrust\host_vector.h" #include "thrust\device_vector.h" using namespace thrust::placeholders; extern __device__ double f(double x); struct f_func { __device__ double operator()(const double& x) const { return f(x); } }; void test(const int len, double * data, double * res) { thrust::device_vector<double> d_data(data, data + len); thrust::transform(d_data.begin(), d_data.end(), d_data.begin(), f_func()); thrust::copy(d_data.begin(),d_data.end(), res); } And a library file that defines f __device__ double f(double x) { return x+2.0; } If I set the option generate relocatable device code to No, the first file will not compile due to unresolved extern function f. If I set it to -rdc, it will compile, but does not produce a device-link.obj file and so the linker fails. If I put the definition of f into the first file and delete the second it builds successfully, but now it isn't separate compilation anymore. How can I build a static library like this with separate source files? [Updated here] I called the first caller file "caller.cu" and the second "libfn.cu". The compiler lines that VS2010 outputs (which I don't fully understand) are (for caller): nvcc.exe -ccbin "C:\Program Files (x86)\Microsoft Visual Studio 10.0\VC\bin" -I"C:\Program Files\NVIDIA GPU Computing Toolkit\CUDA\v5.0\include" -I"C:\Program Files\NVIDIA GPU Computing Toolkit\CUDA\v5.0\include" -G --keep-dir "Debug" -maxrregcount=0 --machine 32 --compile -g -D_MBCS -Xcompiler "/EHsc /W3 /nologo /Od /Zi /RTC1 /MDd " -o "Debug\caller.cu.obj" "G:\Test_Linking\caller.cu" -clean and the same for libfn, then: nvcc.exe -gencode=arch=compute_20,code=\"sm_20,compute_20\" --use-local-env --cl-version 2010 -ccbin "C:\Program Files (x86)\Microsoft Visual Studio 10.0\VC\bin" -rdc=true -I"C:\Program Files\NVIDIA GPU Computing Toolkit\CUDA\v5.0\include" -I"C:\Program Files\NVIDIA GPU Computing Toolkit\CUDA\v5.0\include" -G --keep-dir "Debug" -maxrregcount=0 --machine 32 --compile -g -D_MBCS -Xcompiler "/EHsc /W3 /nologo /Od /Zi /RTC1 /MDd " -o "Debug\caller.cu.obj" "G:\Test_Linking\caller.cu" and again for libfn.

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  • Using a map with set_intersection

    - by Robin Welch
    Not used set_intersection before, but I believe it will work with maps. I wrote the following example code but it doesn't give me what I'd expect: #include <map> #include <string> #include <iostream> #include <algorithm> using namespace std; struct Money { double amount; string currency; bool operator< ( const Money& rhs ) const { if ( amount != rhs.amount ) return ( amount < rhs.amount ); return ( currency < rhs.currency ); } }; int main( int argc, char* argv[] ) { Money mn[] = { { 2.32, "USD" }, { 2.76, "USD" }, { 4.30, "GBP" }, { 1.21, "GBP" }, { 1.37, "GBP" }, { 6.74, "GBP" }, { 2.55, "EUR" } }; typedef pair< int, Money > MoneyPair; typedef map< int, Money > MoneyMap; MoneyMap map1; map1.insert( MoneyPair( 1, mn[1] ) ); map1.insert( MoneyPair( 2, mn[2] ) ); map1.insert( MoneyPair( 3, mn[3] ) ); // (3) map1.insert( MoneyPair( 4, mn[4] ) ); // (4) MoneyMap map2; map1.insert( MoneyPair( 3, mn[3] ) ); // (3) map1.insert( MoneyPair( 4, mn[4] ) ); // (4) map1.insert( MoneyPair( 5, mn[5] ) ); map1.insert( MoneyPair( 6, mn[6] ) ); map1.insert( MoneyPair( 7, mn[7] ) ); MoneyMap out; MoneyMap::iterator out_itr( out.begin() ); set_intersection( map1.begin(), map1.end(), map2.begin(), map2.end(), inserter( out, out_itr ) ); cout << "intersection has " << out.size() << " elements." << endl; return 0; } Since the pair labelled (3) and (4) appear in both maps, I was expecting that I'd get 2 elements in the intersection, but no, I get: intersection has 0 elements. I'm sure this is something to do with the comparitor on the map / pair but can't figure it out.

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  • Simplest way to flatten document to a view in RavenDB

    - by degorolls
    Given the following classes: public class Lookup { public string Code { get; set; } public string Name { get; set; } } public class DocA { public string Id { get; set; } public string Name { get; set; } public Lookup Currency { get; set; } } public class ViewA // Simply a flattened version of the doc { public string Id { get; set; } public string Name { get; set; } public string CurrencyName { get; set; } // View just gets the name of the currency } I can create an index that allows client to query the view as follows: public class A_View : AbstractIndexCreationTask<DocA, ViewA> { public A_View() { Map = docs => from doc in docs select new ViewA { Id = doc.Id, Name = doc.Name, CurrencyName = doc.Currency.Name }; Reduce = results => from result in results group on new ViewA { Id = result.Id, Name = result.Name, CurrencyName = result.CurrencyName } into g select new ViewA { Id = g.Key.Id, Name = g.Key.Name, CurrencyName = g.Key.CurrencyName }; } } This certainly works and produces the desired result of a view with the data transformed to the structure required at the client application. However, it is unworkably verbose, will be a maintenance nightmare and is probably fairly inefficient with all the redundant object construction. Is there a simpler way of creating an index with the required structure (ViewA) given a collection of documents (DocA)? FURTHER INFORMATION The issue appears to be that in order to have the index hold the data in the transformed structure (ViewA), we have to do a Reduce. It appears that a Reduce must have both a GROUP ON and a SELECT in order to work as expected so the following are not valid: INVALID REDUCE CLAUSE 1: Reduce = results => from result in results group on new ViewA { Id = result.Id, Name = result.Name, CurrencyName = result.CurrencyName } into g select g.Key; This produces: System.InvalidOperationException: Variable initializer select must have a lambda expression with an object create expression Clearly we need to have the 'select new'. INVALID REDUCE CLAUSE 2: Reduce = results => from result in results select new ViewA { Id = result.Id, Name = result.Name, CurrencyName = result.CurrencyName }; This prduces: System.InvalidCastException: Unable to cast object of type 'ICSharpCode.NRefactory.Ast.IdentifierExpression' to type 'ICSharpCode.NRefactory.Ast.InvocationExpression'. Clearly, we also need to have the 'group on new'. Thanks for any assistance you can provide. (Note: removing the type (ViewA) from the constructor calls has no effect on the above)

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  • gcc, strict-aliasing, and casting through a union

    - by Joseph Quinsey
    About a year ago the following paragraph was added to the GCC Manual, version 4.3.4, regarding -fstrict-aliasing: Similarly, access by taking the address, casting the resulting pointer and dereferencing the result has undefined behavior [emphasis added], even if the cast uses a union type, e.g.: union a_union { int i; double d; }; int f() { double d = 3.0; return ((union a_union *)&d)->i; } Does anyone have an example to illustrate this undefined behavior? Note this question is not about what the C99 standard says, or does not say. It is about the actual functioning of gcc, and other existing compilers, today. My simple, naive, attempt fails. For example: #include <stdio.h> union a_union { int i; double d; }; int f1(void) { union a_union t; t.d = 3333333.0; return t.i; // gcc manual: 'type-punning is allowed, provided ...' } int f2(void) { double d = 3333333.0; return ((union a_union *)&d)->i; // gcc manual: 'undefined behavior' } int main(void) { printf("%d\n", f1()); printf("%d\n", f2()); return 0; } works fine, giving on CYGWIN: -2147483648 -2147483648 Also note that taking addresses is obviously wrong (or right, if you are trying to illustrate undefined behavior). For example, just as we know this is wrong: extern void foo(int *, double *); union a_union t; t.d = 3.0; foo(&t.i, &t.d); // UD behavior so is this wrong: extern void foo(int *, double *); double d = 3.0; foo(&((union a_union *)&d)->i, &d); // UD behavior For background discussion about this, see for example: http://www.open-std.org/jtc1/sc22/wg14/www/docs/n1422.pdf http://gcc.gnu.org/ml/gcc/2010-01/msg00013.html http://davmac.wordpress.com/2010/02/26/c99-revisited/ http://cellperformance.beyond3d.com/articles/2006/06/understanding-strict-aliasing.html http://stackoverflow.com/questions/98650/what-is-the-strict-aliasing-rule http://stackoverflow.com/questions/2771023/c99-strict-aliasing-rules-in-c-gcc/2771041#2771041 The first link, draft minutes of an ISO meeting seven months ago, notes in section 4.16: Is there anybody that thinks the rules are clear enough? No one is really able to interpret tham.

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  • PHP use of undefined constant error

    - by user272899
    Using a great script to grab details from imdb, I would like to thank Fabian Beiner. Just one error i have encountered with it is: Use of undefined constant sys_get_temp_dir assumed 'sys_get_temp_dir' in '/path/to/directory' on line 49 This is the complete script <?php /** * IMDB PHP Parser * * This class can be used to retrieve data from IMDB.com with PHP. This script will fail once in * a while, when IMDB changes *anything* on their HTML. Guys, it's time to provide an API! * * @link http://fabian-beiner.de * @copyright 2010 Fabian Beiner * @author Fabian Beiner (mail [AT] fabian-beiner [DOT] de) * @license MIT License * * @version 4.1 (February 1st, 2010) * */ class IMDB { private $_sHeader = null; private $_sSource = null; private $_sUrl = null; private $_sId = null; public $_bFound = false; private $_oCookie = '/tmp/imdb-grabber-fb.tmp'; const IMDB_CAST = '#<a href="/name/(\w+)/" onclick="\(new Image\(\)\)\.src=\'/rg/castlist/position-(\d|\d\d)/images/b\.gif\?link=/name/(\w+)/\';">(.*)</a>#Ui'; const IMDB_COUNTRY = '#<a href="/Sections/Countries/(\w+)/">#Ui'; const IMDB_DIRECTOR = '#<a href="/name/(\w+)/" onclick="\(new Image\(\)\)\.src=\'/rg/directorlist/position-(\d|\d\d)/images/b.gif\?link=name/(\w+)/\';">(.*)</a><br/>#Ui'; const IMDB_GENRE = '#<a href="/Sections/Genres/(\w+|\w+\-\w+)/">(\w+|\w+\-\w+)</a>#Ui'; const IMDB_MPAA = '#<h5><a href="/mpaa">MPAA</a>:</h5>\s*<div class="info-content">\s*(.*)\s*</div>#Ui'; const IMDB_PLOT = '#<h5>Plot:</h5>\s*<div class="info-content">\s*(.*)\s*<a#Ui'; const IMDB_POSTER = '#<a name="poster" href="(.*)" title="(.*)"><img border="0" alt="(.*)" title="(.*)" src="(.*)" /></a>#Ui'; const IMDB_RATING = '#<b>(\d\.\d/10)</b>#Ui'; const IMDB_RELEASE_DATE = '#<h5>Release Date:</h5>\s*\s*<div class="info-content">\s*(.*) \((.*)\)#Ui'; const IMDB_RUNTIME = '#<h5>Runtime:</h5>\s*<div class="info-content">\s*(.*)\s*</div>#Ui'; const IMDB_SEARCH = '#<b>Media from&nbsp;<a href="/title/tt(\d+)/"#i'; const IMDB_TAGLINE = '#<h5>Tagline:</h5>\s*<div class="info-content">\s*(.*)\s*</div>#Ui'; const IMDB_TITLE = '#<title>(.*) \((.*)\)</title>#Ui'; const IMDB_URL = '#http://(.*\.|.*)imdb.com/(t|T)itle(\?|/)(..\d+)#i'; const IMDB_VOTES = '#&nbsp;&nbsp;<a href="ratings" class="tn15more">(.*) votes</a>#Ui'; const IMDB_WRITER = '#<a href="/name/(\w+)/" onclick="\(new Image\(\)\)\.src=\'/rg/writerlist/position-(\d|\d\d)/images/b\.gif\?link=name/(\w+)/\';">(.*)</a>#Ui'; const IMDB_REDIRECT = '#Location: (.*)#'; /** * Public constructor. * * @param string $sSearch */ public function __construct($sSearch) { if (function_exists(sys_get_temp_dir)) { $this->_oCookie = tempnam(sys_get_temp_dir(), 'imdb'); } $sUrl = $this->findUrl($sSearch); if ($sUrl) { $bFetch = $this->fetchUrl($this->_sUrl); $this->_bFound = true; } } /** * Little REGEX helper. * * @param string $sRegex * @param string $sContent * @param int $iIndex; */ private function getMatch($sRegex, $sContent, $iIndex = 1) { preg_match($sRegex, $sContent, $aMatches); if ($iIndex > count($aMatches)) return; if ($iIndex == null) { return $aMatches; } return $aMatches[(int)$iIndex]; } /** * Little REGEX helper, I should find one that works for both... ;/ * * @param string $sRegex * @param int $iIndex; */ private function getMatches($sRegex, $iIndex = null) { preg_match_all($sRegex, $this->_sSource, $aMatches); if ((int)$iIndex) return $aMatches[$iIndex]; return $aMatches; } /** * Save an image. * * @param string $sUrl */ private function saveImage($sUrl) { $sUrl = trim($sUrl); $bolDir = false; if (!is_dir(getcwd() . '/posters')) { if (mkdir(getcwd() . '/posters', 0777)) { $bolDir = true; } } $sFilename = getcwd() . '/posters/' . preg_replace("#[^0-9]#", "", basename($sUrl)) . '.jpg'; if (file_exists($sFilename)) { return 'posters/' . basename($sFilename); } if (is_dir(getcwd() . '/posters') OR $bolDir) { if (function_exists('curl_init')) { $oCurl = curl_init($sUrl); curl_setopt_array($oCurl, array ( CURLOPT_VERBOSE => 0, CURLOPT_HEADER => 0, CURLOPT_RETURNTRANSFER => 1, CURLOPT_TIMEOUT => 5, CURLOPT_CONNECTTIMEOUT => 5, CURLOPT_REFERER => $sUrl, CURLOPT_BINARYTRANSFER => 1)); $sOutput = curl_exec($oCurl); curl_close($oCurl); $oFile = fopen($sFilename, 'x'); fwrite($oFile, $sOutput); fclose($oFile); return 'posters/' . basename($sFilename); } else { $oImg = imagecreatefromjpeg($sUrl); imagejpeg($oImg, $sFilename); return 'posters/' . basename($sFilename); } return false; } return false; } /** * Find a valid Url out of the passed argument. * * @param string $sSearch */ private function findUrl($sSearch) { $sSearch = trim($sSearch); if ($aUrl = $this->getMatch(self::IMDB_URL, $sSearch, 4)) { $this->_sId = 'tt' . preg_replace('[^0-9]', '', $aUrl); $this->_sUrl = 'http://www.imdb.com/title/' . $this->_sId .'/'; return true; } else { $sTemp = 'http://www.imdb.com/find?s=all&q=' . str_replace(' ', '+', $sSearch) . '&x=0&y=0'; $bFetch = $this->fetchUrl($sTemp); if( $this->isRedirect() ) { return true; } else if ($bFetch) { if ($strMatch = $this->getMatch(self::IMDB_SEARCH, $this->_sSource)) { $this->_sUrl = 'http://www.imdb.com/title/tt' . $strMatch . '/'; unset($this->_sSource); return true; } } } return false; } /** * Find if result is redirected directly to exact movie. */ private function isRedirect() { if ($strMatch = $this->getMatch(self::IMDB_REDIRECT, $this->_sHeader)) { $this->_sUrl = $strMatch; unset($this->_sSource); unset($this->_sHeader); return true; } return false; } /** * Fetch data from given Url. * Uses cURL if installed, otherwise falls back to file_get_contents. * * @param string $sUrl * @param int $iTimeout; */ private function fetchUrl($sUrl, $iTimeout = 15) { $sUrl = trim($sUrl); if (function_exists('curl_init')) { $oCurl = curl_init($sUrl); curl_setopt_array($oCurl, array ( CURLOPT_VERBOSE => 0, CURLOPT_HEADER => 1, CURLOPT_FRESH_CONNECT => true, CURLOPT_RETURNTRANSFER => 1, CURLOPT_TIMEOUT => (int)$iTimeout, CURLOPT_CONNECTTIMEOUT => (int)$iTimeout, CURLOPT_REFERER => $sUrl, CURLOPT_FOLLOWLOCATION => 0, CURLOPT_COOKIEFILE => $this->_oCookie, CURLOPT_COOKIEJAR => $this->_oCookie, CURLOPT_USERAGENT => 'Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US; rv:1.9.2) Gecko/20100115 Firefox/3.6' )); $sOutput = curl_exec($oCurl); if ($sOutput === false) { return false; } $aInfo = curl_getinfo($oCurl); if ($aInfo['http_code'] != 200 && $aInfo['http_code'] != 302) { return false; } $sTmpHeader = strpos($sOutput, "\r\n\r\n"); $this->_sHeader = substr($sOutput, 0, $sTmpHeader); $this->_sSource = str_replace("\n", '', substr($sOutput, $sTmpHeader+1)); curl_close($oCurl); return true; } else { $sOutput = @file_get_contents($sUrl, 0); if (strpos($http_response_header[0], '200') === false){ return false; } $this->_sSource = str_replace("\n", '', (string)$sOutput); return true; } return false; } /** * Returns the cast. */ public function getCast($iOutput = null, $bMore = true) { if ($this->_sSource) { $sReturned = $this->getMatches(self::IMDB_CAST, 4); if (is_array($sReturned)) { if ($iOutput) { foreach ($sReturned as $i => $sName) { if ($i >= $iOutput) break; $sReturn[] = $sName; } return implode(' / ', $sReturn) . (($bMore) ? '&hellip;' : ''); } return implode(' / ', $sReturned); } return $sReturned; } return 'n/A'; } /** * Returns the cast as links. */ public function getCastAsUrl($iOutput = null, $bMore = true) { if ($this->_sSource) { $sReturned1 = $this->getMatches(self::IMDB_CAST, 4); $sReturned2 = $this->getMatches(self::IMDB_CAST, 3); if (is_array($sReturned1)) { if ($iOutput) { foreach ($sReturned1 as $i => $sName) { if ($i >= $iOutput) break; $aReturn[] = '<a href="http://www.imdb.com/name/' . $sReturned2[$i] . '/">' . $sName . '</a>';; } return implode(' / ', $aReturn) . (($bMore) ? '&hellip;' : ''); } return implode(' / ', $sReturned); } return '<a href="http://www.imdb.com/name/' . $sReturned2 . '/">' . $sReturned1 . '</a>';; } return 'n/A'; } /** * Returns the countr(y|ies). */ public function getCountry() { if ($this->_sSource) { $sReturned = $this->getMatches(self::IMDB_COUNTRY, 1); if (is_array($sReturned)) { return implode(' / ', $sReturned); } return $sReturned; } return 'n/A'; } /** * Returns the countr(y|ies) as link(s). */ public function getCountryAsUrl() { if ($this->_sSource) { $sReturned = $this->getMatches(self::IMDB_COUNTRY, 1); if (is_array($sReturned)) { foreach ($sReturned as $sCountry) { $aReturn[] = '<a href="http://www.imdb.com/Sections/Countries/' . $sCountry . '/">' . $sCountry . '</a>'; } return implode(' / ', $aReturn); } return '<a href="http://www.imdb.com/Sections/Countries/' . $sReturned . '/">' . $sReturned . '</a>'; } return 'n/A'; } /** * Returns the director(s). */ public function getDirector() { if ($this->_sSource) { $sReturned = $this->getMatches(self::IMDB_DIRECTOR, 4); if (is_array($sReturned)) { return implode(' / ', $sReturned); } return $sReturned; } return 'n/A'; } /** * Returns the director(s) as link(s). */ public function getDirectorAsUrl() { if ($this->_sSource) { $sReturned1 = $this->getMatches(self::IMDB_DIRECTOR, 4); $sReturned2 = $this->getMatches(self::IMDB_DIRECTOR, 1); if (is_array($sReturned1)) { foreach ($sReturned1 as $i => $sDirector) { $aReturn[] = '<a href="http://www.imdb.com/name/' . $sReturned2[$i] . '/">' . $sDirector . '</a>'; } return implode(' / ', $aReturn); } return '<a href="http://www.imdb.com/name/' . $sReturned2 . '/">' . $sReturned1 . '</a>'; } return 'n/A'; } /** * Returns the genre(s). */ public function getGenre() { if ($this->_sSource) { $sReturned = $this->getMatches(self::IMDB_GENRE, 1); if (is_array($sReturned)) { return implode(' / ', $sReturned); } return $sReturned; } return 'n/A'; } /** * Returns the genre(s) as link(s). */ public function getGenreAsUrl() { if ($this->_sSource) { $sReturned = $this->getMatches(self::IMDB_GENRE, 1); if (is_array($sReturned)) { foreach ($sReturned as $i => $sGenre) { $aReturn[] = '<a href="http://www.imdb.com/Sections/Genres/' . $sGenre . '/">' . $sGenre . '</a>'; } return implode(' / ', $aReturn); } return '<a href="http://www.imdb.com/Sections/Genres/' . $sReturned . '/">' . $sReturned . '</a>'; } return 'n/A'; } /** * Returns the mpaa. */ public function getMpaa() { if ($this->_sSource) { return implode('' , $this->getMatches(self::IMDB_MPAA, 1)); } return 'n/A'; } /** * Returns the plot. */ public function getPlot() { if ($this->_sSource) { return implode('' , $this->getMatches(self::IMDB_PLOT, 1)); } return 'n/A'; } /** * Download the poster, cache it and return the local path to the image. */ public function getPoster() { if ($this->_sSource) { if ($sPoster = $this->saveImage(implode("", $this->getMatches(self::IMDB_POSTER, 5)), 'poster.jpg')) { return $sPoster; } return implode('', $this->getMatches(self::IMDB_POSTER, 5)); } return 'n/A'; } /** * Returns the rating. */ public function getRating() { if ($this->_sSource) { return implode('', $this->getMatches(self::IMDB_RATING, 1)); } return 'n/A'; } /** * Returns the release date. */ public function getReleaseDate() { if ($this->_sSource) { return implode('', $this->getMatches(self::IMDB_RELEASE_DATE, 1)); } return 'n/A'; } /** * Returns the runtime of the current movie. */ public function getRuntime() { if ($this->_sSource) { return implode('', $this->getMatches(self::IMDB_RUNTIME, 1)); } return 'n/A'; } /** * Returns the tagline. */ public function getTagline() { if ($this->_sSource) { return implode('', $this->getMatches(self::IMDB_TAGLINE, 1)); } return 'n/A'; } /** * Get the release date of the current movie. */ public function getTitle() { if ($this->_sSource) { return implode('', $this->getMatches(self::IMDB_TITLE, 1)); } return 'n/A'; } /** * Returns the url. */ public function getUrl() { return $this->_sUrl; } /** * Get the votes of the current movie. */ public function getVotes() { if ($this->_sSource) { return implode('', $this->getMatches(self::IMDB_VOTES, 1)); } return 'n/A'; } /** * Get the year of the current movie. */ public function getYear() { if ($this->_sSource) { return implode('', $this->getMatches(self::IMDB_TITLE, 2)); } return 'n/A'; } /** * Returns the writer(s). */ public function getWriter() { if ($this->_sSource) { $sReturned = $this->getMatches(self::IMDB_WRITER, 4); if (is_array($sReturned)) { return implode(' / ', $sReturned); } return $sReturned; } return 'n/A'; } /** * Returns the writer(s) as link(s). */ public function getWriterAsUrl() { if ($this->_sSource) { $sReturned1 = $this->getMatches(self::IMDB_WRITER, 4); $sReturned2 = $this->getMatches(self::IMDB_WRITER, 1); if (is_array($sReturned1)) { foreach ($sReturned1 as $i => $sWriter) { $aReturn[] = '<a href="http://www.imdb.com/name/' . $sReturned2[$i] . '/">' . $sWriter . '</a>'; } return implode(' / ', $aReturn); } return '<a href="http://www.imdb.com/name/' . $sReturned2 . '/">' . $sReturned1 . '</a>'; } return 'n/A'; } } ?>

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  • Should I add try/catch around when casting on an attribute of JSP implicit object?

    - by Michael Mao
    Hi all: Basically what I mean is like this: List<String[]> routes = (List<String[]>)application.getAttribute("routes"); For the above code, it tries to get an attribute named "routes" from the JSP implicit object - application. But as everyone knows, after this line of code, routes may very well contains a null - which means this application hasn't got an attribute named "routes". Is this "casting on null" good programming practice in Java or not? Basically I try to avoid exceptions such as java.io.InvalidCastException I reckon things like this are more as "heritage" of Java 1.4 when generic types were not introduced to this language. So I guess everything stored in application attributes as Objects (Similar to traditional ArrayList). And when you do "downcast", there might be invalid casts. What would you do in this case? Update: Just found that although in the implicit object application I did store a List of String arrays, when I do this : List<double[]> routes = (List<double[]>)application.getAttribute("routes"); It doesn't produce any error... And I felt not comfortable already... And even with this code: out.print(routes.get(0)); It does print out something strange : [Ljava.lang.String;@18b352f Am I printing a "pointer to String"? I can finally get an exception like this: out.print(routes.get(0)[1]); with error : java.lang.ClassCastException: [Ljava.lang.String; Because it was me to add the application attribute, I know which type should it be cast to. I feel this is not "good enough", what if I forget the exact type? I know there are still some cases where this sort of thing would happen, such as in JSP/Servlet when you do casting on session attributes. Is there a better way to do this? Before you say:"OMG, why you don't use Servlets???", I should justify my reason as this: - because my uni sucks, its server can only work with Servlets generated by JSP, and I don't really want to learn how to fix issues like that. look at my previous question on this , and this is uni homework, so I've got no other choice, forget all about war, WEB-INF,etc, but "code everything directly into JSP" - because the professors do that too. :)

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  • Changing backgroundcolor in listview (expandable listview)

    - by Stofke
    I'm trying to dynamically change a backgroundcolor in a part of a listview, I have on example that works fine in a listview when I try to replicate it in another part with an expandable listview it fails This piece of code works and displays a different color if a student is online or not ... map.put(KEY_FIRSTNAME, temp.firstName); map.put(KEY_NAME, temp.name); map.put(KEY_EMAIL, temp.email); map.put(KEY_ISONLINE, temp.isOnLine); // change image if student is online or not Log.d("demo", "is on line= " + temp.isOnLine); if (temp.isOnLine.equalsIgnoreCase("1")) { map.put(KEY_IMAGE_ISONLINE, R.color.greenColor); } else { map.put(KEY_IMAGE_ISONLINE, R.color.greyColor); } listItem.add(map); } myListView = (ListView) findViewById(R.id.listViewTabLeerlingen); SimpleAdapter adapter = new SimpleAdapter(StudentTab.this, listItem, R.layout.list_item_student, new String[] { KEY_FIRSTNAME, KEY_NAME, KEY_IMAGE_ISONLINE }, new int[] { R.id.firstNameTextView, R.id.lastNameTextView, R.id.logo }); myListView.setAdapter(adapter); the xml that goes along with it <ImageView android:id="@+id/logo" android:layout_width="85dp" android:layout_height="match_parent" android:background="@color/greenColor" android:contentDescription="Image if student is online or not" android:src="@drawable/transparent_pixel" /> The above works fine however the following code (just part of the code) ... ArrayList<Map<String, Object>> children = new ArrayList<Map<String, Object>>(); for (int i = 0; i < _data.length(); i++) { try { JSONArray tmp = _data.getJSONArray(i); HashMap<String, Object> map = new HashMap<String, Object>(); // change image if student is online or not if (tmp.getString(3).equalsIgnoreCase("0")) { map.put(KEY_POINTS,R.color.redColor); }else{ map.put(KEY_POINTS,R.color.greenColor); } map.put(KEY_QUESTIONTEXT, tmp.getString(1)); map.put(KEY_ANSWER, tmp.getString(2)); children.add(map); } catch (JSONException e) { e.printStackTrace(); } childData.add(children); ... ... ArrayList<ArrayList<Map<String, Object>>> childData) { SimpleExpandableListAdapter listAdapter = new SimpleExpandableListAdapter( this, groupData, R.layout.list_item_results_students, new String[] { KEY_FIRSTNAME, KEY_NAME, KEY_ISJUIST }, new int[] { R.id.firstnameResults, R.id.nameResults, R.id.resultsTextView }, childData, R.layout.list_item_results_results, new String[] { KEY_QUESTIONTEXT, KEY_ANSWER, KEY_POINTS }, new int[] { R.id.questionTextView, R.id.answerTextTextView, R.id.score }); ExpandableListView myListView = (ExpandableListView) findViewById(R.id.listViewTabResultaten); myListView.setAdapter(listAdapter); with xml: <ImageView android:id="@+id/score" android:layout_width="16dp" android:layout_height="match_parent" android:background="@color/greenColor" android:contentDescription="Image if student has correct answer" android:src="@drawable/transparent_pixel" /> I will get this error: 06-09 10:35:21.490: E/AndroidRuntime(4406): java.lang.ClassCastException: android.widget.ImageView cannot be cast to android.widget.TextView

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  • Stored procedure error when use computed column for ID

    - by Hari
    I got the error: Procedure or function usp_User_Info3 has too many arguments specified When I run the program. I don't know the error in SP or in C# code. I have to display the Vendor_ID after the user clicks the submit button. Where the thing going wrong here ? Table structure : CREATE TABLE User_Info3 ( SNo int Identity (2000,1) , Vendor_ID AS 'VEN' + CAST(SNo as varchar(16)) PERSISTED PRIMARY KEY, UserName VARCHAR(16) NOT NULL, User_Password VARCHAR(12) NOT NULL, User_ConPassword VARCHAR(12) NOT NULL, User_FirstName VARCHAR(25) NOT NULL, User_LastName VARCHAR(25) SPARSE NULL, User_Title VARCHAR(35) NOT NULL, User_EMail VARCHAR(35) NOT NULL, User_PhoneNo VARCHAR(14) NOT NULL, User_MobileNo VARCHAR(14)NOT NULL, User_FaxNo VARCHAR(14)NOT NULL, UserReg_Date DATE DEFAULT GETDATE() ) Stored Procedure : ALTER PROCEDURE [dbo].[usp_User_Info3] @SNo INT OUTPUT, @Vendor_ID VARCHAR(10) OUTPUT, @UserName VARCHAR(30), @User_Password VARCHAR(12), @User_ConPassword VARCHAR(12), @User_FirstName VARCHAR(25), @User_LastName VARCHAR(25), @User_Title VARCHAR(35), @User_OtherEmail VARCHAR(30), @User_PhoneNo VARCHAR(14), @User_MobileNo VARCHAR(14), @User_FaxNo VARCHAR(14) AS BEGIN SET NOCOUNT ON; INSERT INTO User_Info3 (UserName,User_Password,User_ConPassword,User_FirstName, User_LastName,User_Title,User_OtherEmail,User_PhoneNo,User_MobileNo,User_FaxNo) VALUES (@UserName,@User_Password,@User_ConPassword,@User_FirstName,@User_LastName, @User_Title,@User_OtherEmail,@User_PhoneNo,@User_MobileNo,@User_FaxNo) SET @SNo = Scope_Identity() SELECT Vendor_ID From User_Info3 WHERE SNo = @SNo END C# Code : protected void BtnUserNext_Click(object sender, EventArgs e) { cmd.CommandType = CommandType.StoredProcedure; cmd.CommandText = "usp_User_Info3"; System.Data.SqlClient.SqlParameter SNo=cmd.Parameters.Add("@SNo",System.Data.SqlDbType.Int); System.Data.SqlClient.SqlParameter Vendor_ID=cmd.Parameters.Add("@Vendor_ID", System.Data.SqlDbType.VarChar,10); cmd.Parameters.Add("@UserName", SqlDbType.VarChar).Value = txtUserName.Text; cmd.Parameters.Add("@User_Password", SqlDbType.VarChar).Value = txtRegPassword.Text; cmd.Parameters.Add("@User_ConPassword", SqlDbType.VarChar).Value = txtRegConPassword.Text; cmd.Parameters.Add("@User_FirstName", SqlDbType.VarChar).Value = txtRegFName.Text; cmd.Parameters.Add("@User_LastName", SqlDbType.VarChar).Value = txtRegLName.Text; cmd.Parameters.Add("@User_Title", SqlDbType.VarChar).Value = txtRegTitle.Text; cmd.Parameters.Add("@User_OtherEmail", SqlDbType.VarChar).Value = txtOtherEmail.Text; cmd.Parameters.Add("@User_PhoneNo", SqlDbType.VarChar).Value =txtRegTelephone.Text; cmd.Parameters.Add("@User_MobileNo", SqlDbType.VarChar).Value =txtRegMobile.Text; cmd.Parameters.Add("@User_FaxNo", SqlDbType.VarChar).Value =txtRegFax.Text; cmd.Connection = SqlCon; try { Vendor_ID.Direction = System.Data.ParameterDirection.Output; SqlCon.Open(); cmd.ExecuteNonQuery(); string VendorID = cmd.ExecuteScalar() as string; } catch (Exception ex) { throw new Exception(ex.Message); } finally { string url = "../CompanyBasicInfo.aspx?Parameter=" + Server.UrlEncode(" + VendorID + "); SqlCon.Close(); } }

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  • How to change quicksort to output elements in descending order?

    - by masato-san
    Hi, I wrote a quicksort algorithm however, I would like to make a change somewhere so that this quicksort would output elements in descending order. I searched and found that I can change the comparison operator (<) in partition() to other way around (like below). //This is snippet from partition() function while($array[$l] < $pivot) { $l++; } while($array[$r] > $pivot) { $r--; } But it is not working.. If I quicksort the array below, $array = (3,9,5,7); should be: $array = (9,7,5,3) But actual output is: $array = (3,5,7,9) Below is my quicksort which trying to output elements in descending order. How should I make change to sort in descending order? If you need any clarification please let me know. Thanks! $array = (3,9,5,7); $app = new QuicksortDescending(); $app->quicksort($array, 0, count($array)); print_r($array); class QuicksortDescending { public function partitionDesc(&$array, $left, $right) { $l = $left; $r = $right; $pivot = $array[($right+$left)/2]; while($l <= $r) { while($array[$l] > $pivot) { $l++; } while($array[$r] < $pivot) { $r--; } if($l <= $r) {// if L and R haven't cross $this->swap($array, $l, $r); $l ++; $j --; } } return $l; } public function quicksortDesc(&$array, $left, $right) { $index = $this->partition($array, $left, $right); if($left < $index-1) { //if there is more than 1 element to sort on right subarray $this->quicksortDesc($array, $left, $index-1); } if($index < $right) { //if there is more than 1 element to sort on right subarray $this->quicksortDesc($array, $index, $right); } } }

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  • Linq query challenge - can this be done?

    - by vdh_ant
    My table structure is as follows: Person 1-M PesonAddress Person 1-M PesonPhone Person 1-M PesonEmail Person 1-M Contract Contract M-M Program Contract M-1 Organization At the end of this query I need a populated object graph where each person has their: PesonAddress's PesonPhone's PesonEmail's PesonPhone's Contract's - and this has its respective Program's Now I had the following query and I thought that it was working great, but it has a couple of problems: from people in ctx.People.Include("PersonAddress") .Include("PersonLandline") .Include("PersonMobile") .Include("PersonEmail") .Include("Contract") .Include("Contract.Program") where people.Contract.Any( contract => (param.OrganizationId == contract.OrganizationId) && contract.Program.Any( contractProgram => (param.ProgramId == contractProgram.ProgramId))) select people; The problem is that it filters the person to the criteria but not the Contracts or the Contract's Programs. It brings back all Contracts that each person has not just the ones that have an OrganizationId of x and the same goes for each of those Contract's Programs respectively. What I want is only the people that have at least one contract with an OrgId of x with and where that contract has a Program with the Id of y... and for the object graph that is returned to have only the contracts that match and programs within that contract that match. I kinda understand why its not working, but I don't know how to change it so it is working... This is my attempt thus far: from people in ctx.People.Include("PersonAddress") .Include("PersonLandline") .Include("PersonMobile") .Include("PersonEmail") .Include("Contract") .Include("Contract.Program") let currentContracts = from contract in people.Contract where (param.OrganizationId == contract.OrganizationId) select contract let currentContractPrograms = from contractProgram in currentContracts let temp = from x in contractProgram.Program where (param.ProgramId == contractProgram.ProgramId) select x where temp.Any() select temp where currentContracts.Any() && currentContractPrograms.Any() select new Person { PersonId = people.PersonId, FirstName = people.FirstName, ..., ...., MiddleName = people.MiddleName, Surname = people.Surname, ..., ...., Gender = people.Gender, DateOfBirth = people.DateOfBirth, ..., ...., Contract = currentContracts, ... }; //This doesn't work But this has several problems (where the Person type is an EF object): I am left to do the mapping by myself, which in this case there is quite a lot to map When ever I try to map a list to a property (i.e. Scholarship = currentScholarships) it says I can't because IEnumerable is trying to be cast to EntityCollection Include doesn't work Hence how do I get this to work. Keeping in mind that I am trying to do this as a compiled query so I think that means anonymous types are out.

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  • ASP.NET MVC: How can I explain an invalid type violation to an end-user with Html.ValidationSummary?

    - by Terminal Frost
    Serious n00b warning here; please take mercy! So I finished the Nerd Dinner MVC Tutorial and I'm now in the process of converting a VB.NET application to ASP.NET MVC using the Nerd Dinner program as a sort of rough template. I am using the "IsValid / GetRuleViolations()" pattern to identify invalid user input or values that violate business rules. I am using LINQ to SQL and am taking advantage of the "OnValidate()" hook that allows me to run the validation and throw an application exception upon trying to save changes to the database via the CustomerRepository class. Anyway, everything works well, except that by the time the form values reach my validation method invalid types have already been converted to a default or existing value. (I have a "StreetNumber" property that is an integer, though I imagine this would be a problem for DateTime or any other non-strings as well.) Now, I am guessing that the UpdateModel() method throws an exception and then alters the value because the Html.ValidationMessage is displayed next to the StreetNumber field but my validation method never sees the original input. There are two problems with this: While the Html.ValidationMessage does signal that something is wrong, there is no corresponding entry in the Html.ValidationSummary. If I could even get the exception message to show up there indicating an invalid cast or something that would be better than nothing. My validation method which resides in my Customer partial class never sees the original user input so I do not know if the problem is a missing entry or an invalid type. I can't figure out how I can keep my validation logic nice and neat in one place and still get access to the form values. I could of course write some logic in the View that processes the user input, however that seems like the exact opposite of what I should be doing with MVC. Do I need a new validation pattern or is there some way to pass the original form values to my model class for processing? CustomerController Code // POST: /Customers/Edit/[id] [AcceptVerbs(HttpVerbs.Post)] public ActionResult Edit(int id, FormCollection formValues) { Customer customer = customerRepository.GetCustomer(id); try { UpdateModel(customer); customerRepository.Save(); return RedirectToAction("Details", new { id = customer.AccountID }); } catch { foreach (var issue in customer.GetRuleViolations()) ModelState.AddModelError(issue.PropertyName, issue.ErrorMessage); } return View(customer); }

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  • using dictionaries with WebServices

    - by umit-alba
    Hi! I tried to pass a dictionary via WebServices. However it is not serializeable. So i wrote an Own Class that makes it serializeable: using System; using System.Net; using System.Windows; using System.Collections.Generic; using System.Xml.Serialization; using System.Xml; using System.Xml.Schema; namespace Platform { public class SaDictionary<TKey, TValue> : Dictionary<TKey, TValue>, IXmlSerializable { #region Constructors public SaDictionary() : base() { } public SaDictionary(IDictionary<TKey, TValue> dictionary) : base(dictionary) { } public SaDictionary(IEqualityComparer<TKey> comparer) : base(comparer) { } public SaDictionary(int capacity) : base(capacity) { } public SaDictionary(IDictionary<TKey, TValue> dictionary, IEqualityComparer<TKey> comparer) : base(dictionary, comparer) { } public SaDictionary(int capacity, IEqualityComparer<TKey> comparer) : base(capacity, comparer) { } //protected SaDictionary(SerializationInfo info, StreamingContext context) // : base(info, context) //{ //} #endregion public XmlSchema GetSchema() { return null; } public void ReadXml(XmlReader reader) { XmlSerializer keySerializer = new XmlSerializer(typeof(TKey)); XmlSerializer valueSerializer = new XmlSerializer(typeof(TValue)); bool wasEmpty = reader.IsEmptyElement; reader.Read(); if (wasEmpty) return; while (reader.NodeType != XmlNodeType.EndElement) { reader.ReadStartElement("item"); reader.ReadStartElement("key"); TKey key = (TKey)keySerializer.Deserialize(reader); reader.ReadEndElement(); //key reader.ReadStartElement("value"); TValue value = (TValue)valueSerializer.Deserialize(reader); reader.ReadEndElement(); //value this.Add(key, value); reader.ReadEndElement(); //item // reader.MoveToContent(); } reader.ReadEndElement(); } public void WriteXml(XmlWriter writer) { XmlSerializer keySerializer = new XmlSerializer(typeof(TKey)); XmlSerializer valueSerializer = new XmlSerializer(typeof(TValue)); foreach (TKey key in this.Keys) { writer.WriteStartElement("item"); writer.WriteStartElement("key"); keySerializer.Serialize(writer, key); writer.WriteEndElement(); //key writer.WriteStartElement("value"); TValue value = this[key]; valueSerializer.Serialize(writer, value); writer.WriteEndElement(); //value writer.WriteEndElement(); //item } } } } However i get an ArrayOfXElement back. Is there a way to cast it back to a Dictionary? greets

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  • Rails Tutorial Chapter 4 2nd Ed. Title Helper not being called with out argument.

    - by SuddenlyAwakened
    I am running through the Rails Tutorial by Michael Hartl (Screen Cast). Ran into the and issue in chapter 4 on the title helper. I have been putting my own twist on the code as I go to make sure I understand it all. However on this one I it is very similar and I am not quite sure why it is acting the way it is. Here is the code: Application.html.erb <!DOCTYPE html> <html> <head> <%- Rails.logger.info("Testing: #{yield(:title)}") %> <title><%= full_title(yield(:title)) %></title> <%= stylesheet_link_tag "application", :media => "all" %> <%= javascript_include_tag "application" %> <%= csrf_meta_tags %> </head> <body> <%= yield %> </body> </html> Application_helper.rb module ApplicationHelper def full_title(page_title) full_title = "Ruby on Rails Tutorial App" full_title += " | #{page_title}" unless page_title.blank? end end Home.html.erb <h1><%= t(:sample_app) %></h1> <p> This is the home page for the <a href="http://railstutorial.org/">Ruby on Rails Tutorial</a> sample application </p> about.html.erb <% provide(:title, t(:about_us)) %> <h1><%= t(:about_us) %></h1> <p> The <a href="http://railstutorial.org/">Ruby on Rails Tutorial</a> is a project to make a book and screencast to teach web development with <a href="http://railstutorial.org/">Ruby on Rails</a>. This is the sample application for the tutorial. </p> What Happens: The code works fine when I set the provide method like on the about page. However when I do not it does not seem to even call the helper. I am assuming that because no title is passed back. Any ideas on what I am doing wrong? Thank you all for your help.

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  • Values of generated column not appearing in table

    - by msh210
    I'm using mysql version 5.1.41-3ubuntu12.10 (Ubuntu). mysql> show create table tt\G *************************** 1. row *************************** Table: tt Create Table: CREATE TABLE `tt` ( `pz` int(8) DEFAULT NULL, `os` varchar(8) DEFAULT NULL, `uz` int(11) NOT NULL, `p` bigint(21) NOT NULL DEFAULT '0', `c` decimal(23,0) DEFAULT NULL, KEY `pz` (`pz`), KEY `uz` (`uz`), KEY `os` (`os`), KEY `pz_2` (`pz`,`uz`) ) ENGINE=MyISAM DEFAULT CHARSET=latin1 1 row in set (0.00 sec) mysql> select pz,uz,pz*uz, -> if(pz*uz,1,.5), -> left(pz,2) pl,left(lpad(uz,5,0),2) ul, -> p from tt limit 10; +-------+----+-------+----------------+--------+----+--------+ | pz | uz | pz*uz | if(pz*uz,1,.5) | pl | ul | p | +-------+----+-------+----------------+--------+----+--------+ | NULL | 0 | NULL | 0.5 | NULL | 00 | 4080 | | NULL | 0 | NULL | 0.5 | NULL | 00 | 323754 | | 89101 | 0 | 0 | 0.5 | 89 | 00 | 6880 | | 0 | 0 | 0 | 0.5 | 0 | 00 | 11591 | | 89110 | 0 | 0 | 0.5 | 89 | 00 | 72 | | 78247 | 0 | 0 | 0.5 | 78 | 00 | 27 | | 90062 | 0 | 0 | 0.5 | 90 | 00 | 5 | | 63107 | 0 | 0 | 0.5 | 63 | 00 | 4 | | NULL | 0 | NULL | 0.5 | NULL | 00 | 54561 | | 94102 | 0 | 0 | 0.5 | 94 | 00 | 12499 | +-------+----+-------+----------------+--------+----+--------+ So far so good. As you see, 0.5 appears as a value of if(pz*uz,1,.5). The problem is: mysql> select os, -> if(pz*uz,left(pz,2)<=>left(lpad(uz,5,0),2),.5) uptwo, -> if(pz*uz,left(pz,3)<=>left(lpad(uz,5,0),3),.5) upthree, -> sum(p) p,sum(c) c -> from tt t -> group by os,uptwo,upthree order by null; +----+-------+---------+---------+-------+ | os | uptwo | upthree | p | c | +----+-------+---------+---------+-------+ | u | 1 | 1 | 52852 | 318 | | i | 1 | 1 | 7046563 | 21716 | | m | 1 | 1 | 1252166 | 7337 | | i | 0 | 0 | 1830284 | 4033 | | m | 0 | 0 | 294612 | 1714 | | i | 1 | 0 | 911486 | 3560 | | m | 1 | 0 | 145182 | 1136 | | u | 0 | 0 | 12144 | 23 | | u | 1 | 0 | 1571 | 8 | +----+-------+---------+---------+-------+ Although I group by uptwo, 0.5 doesn't appear in that column. What happened to the 0.5 values? Edit: As noted in the comments to Todd Gibson's answer, I also tried it with if(pz*uz,cast(left(pz,2)<=>left(lpad(uz,5,0),2) as decimal),.5) instead of if(pz*uz,left(pz,2)<=>left(lpad(uz,5,0),2),.5), but it, too, didn't work.

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  • Specializating a template function that takes a universal reference parameter

    - by David Stone
    How do I specialize a template function that takes a universal reference parameter? foo.hpp: template<typename T> void foo(T && t) // universal reference parameter foo.cpp template<> void foo<Class>(Class && class) { // do something complicated } Here, Class is no longer a deduced type and thus is Class exactly; it cannot possibly be Class &, so reference collapsing rules will not help me here. I could perhaps create another specialization that takes a Class & parameter (I'm not sure), but that implies duplicating all of the code contained within foo for every possible combination of rvalue / lvalue references for all parameters, which is what universal references are supposed to avoid. Is there some way to accomplish this? To be more specific about my problem in case there is a better way to solve it: I have a program that can connect to multiple game servers, and each server, for the most part, calls everything by the same name. However, they have slightly different versions for a few things. There are a few different categories that these things can be: a move, an item, etc. I have written a generic sort of "move string to move enum" set of functions for internal code to call, and my server interface code has similar functions. However, some servers have their own internal ID that they communicate with, some use strings, and some use both in different situations. Now what I want to do is make this a little more generic. I want to be able to call something like ServerNamespace::server_cast<Destination>(source). This would allow me to cast from a Move to a std::string or ServerMoveID. Internally, I may need to make a copy (or move from) because some servers require that I keep a history of messages sent. Universal references seem to be the obvious solution to this problem. The header file I'm thinking of right now would expose simply this: namespace ServerNamespace { template<typename Destination, typename Source> Destination server_cast(Source && source); } And the implementation file would define all legal conversions as template specializations.

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  • how to update an Android ListActivity on changing data of the connected SimpleCursorAdapter

    - by 4485670
    I have the following code. What I want to achieve is to update the shown list when I click an entry so I can traverse through the list. I found the two uncommented ways to do it here on stackoverflow, but neither works. I also got the advice to create a new ListActivity on the data update, but that sounds like wasting resources? EDIT: I found the solution myself. All you need to do is call "SimpleCursorAdapter.changeCursor(new Cursor);". No notifying, no things in UI-Thread or whatever. import android.app.ListActivity; import android.database.Cursor; import android.os.Bundle; import android.util.Log; import android.view.View; import android.widget.ListView; import android.widget.SimpleCursorAdapter; public class MyActivity extends ListActivity { private DepartmentDbAdapter mDbHelper; private Cursor cursor; private String[] from = new String[] { DepartmentDbAdapter.KEY_NAME }; private int[] to = new int[] { R.id.text1 }; private SimpleCursorAdapter notes; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.departments_list); mDbHelper = new DepartmentDbAdapter(this); mDbHelper.open(); // Get all of the departments from the database and create the item list cursor = mDbHelper.fetchSubItemByParentId(1); this.startManagingCursor(cursor); // Now create an array adapter and set it to display using our row notes = new SimpleCursorAdapter(this, R.layout.department_row, cursor, from, to); this.setListAdapter(notes); } @Override protected void onListItemClick(ListView l, View v, int position, long id) { super.onListItemClick(l, v, position, id); // get new data and update the list this.updateData(safeLongToInt(id)); } /** * update data for the list * * @param int departmentId id of the parent department */ private void updateData(int departmentId) { // close the old one, get a new one cursor.close(); cursor = mDbHelper.fetchSubItemByParentId(departmentId); // change the cursor of the adapter to the new one notes.changeCursor(cursor); } /** * safely convert long to in to save memory * * @param long l the long variable * * @return integer */ public static int safeLongToInt(long l) { if (l < Integer.MIN_VALUE || l > Integer.MAX_VALUE) { throw new IllegalArgumentException (l + " cannot be cast to int without changing its value."); } return (int) l; } }

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  • initializing a vector of custom class in c++

    - by Flamewires
    Hey basically Im trying to store a "solution" and create a vector of these. The problem I'm having is with initialization. Heres my class for reference class Solution { private: // boost::thread m_Thread; int itt_found; int dim; pfn_fitness f; double value; std::vector<double> x; public: Solution(size_t size, int funcNo) : itt_found(0), x(size, 0.0), value(0.0), dim(30), f(Eval_Functions[funcNo]) { for (int i = 1; i < (int) size; i++) { x[i] = ((double)rand()/((double)RAND_MAX))*maxs[funcNo]; } } Solution() : itt_found(0), x(31, 0.0), value(0.0), dim(30), f(Eval_Functions[1]) { for (int i = 1; i < 31; i++) { x[i] = ((double)rand()/((double)RAND_MAX))*maxs[1]; } } Solution operator= (Solution S) { x = S.GetX(); itt_found = S.GetIttFound(); dim = S.GetDim(); f = S.GetFunc(); value = S.GetValue(); return *this; } void start() { value = f (dim, x); } /* plus additional getter/setter methods*/ } Solution S(30, 1) or Solution(2, 5) work and initalizes everything, but I need X of these solution objects. std::vector<Solution> Parents(X) will create X solutions with the default constructor and i want to construct using the (int, int) constructor. Is there any easy(one liner?) way to do this? Or would i have to do something like: size_t numparents = 10; vector<Solution> Parents; Parents.reserve(numparents); for (int i = 0; i<(int)numparents; i++) { Solution S(31, 0); Parents.push_back(S); }

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  • Remove never-run call to templated function, get allocation error on run-time

    - by Narfanator
    First off, I'm a bit at a loss as to how to ask this question. So I'm going to try throwing lots of information at the problem. Ok, so, I went to completely redesign my test project for my experimental core library thingy. I use a lot of template shenanigans in the library. When I removed the "user" code, the tests gave me a memory allocation error. After quite a bit of experimenting, I narrowed it down to this bit of code (out of a couple hundred lines): void VOODOO(components::switchBoard &board){ board.addComponent<using_allegro::keyInputs<'w'> >(); } Fundementally, what's weirding me out is that it appears that the act of compiling this function (and the template function it then uses, and the template functions those then use...), makes this bug not appear. This code is not being run. Similar code (the same, but for different key vals) occurs elsewhere, but is within Boost TDD code. I realize I certainly haven't given enough information for you to solve it for me; I tried, but it more-or-less spirals into most of the code base. I think I'm most looking for "here's what the problem could be", "here's where to look", etc. There's something that's happening during compile because of this line, but I don't know enough about that step to begin looking. Sooo, how can a (presumably) compilied, but never actually run, bit of templated code, when removed, cause another part of code to fail? Error: Unhandled exceptionat 0x6fe731ea (msvcr90d.dll) in Switchboard.exe: 0xC0000005: Access violation reading location 0xcdcdcdc1. Callstack: operator delete(void * pUser Data) allocator< class name related to key inputs callbacks ::deallocate vector< same class ::_Insert_n(...) vector< " " ::insert(...) vector<" "::push_back(...) It looks like maybe the vector isn't valid, because _MyFirst and similar data members are showing values of 0xcdcdcdcd in the debugger. But the vector is a member variable...

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  • C++ string sort like a human being?

    - by Walter Nissen
    I would like to sort alphanumeric strings the way a human being would sort them. I.e., "A2" comes before "A10", and "a" certainly comes before "Z"! Is there any way to do with without writing a mini-parser? Ideally it would also put "A1B1" before "A1B10". I see the question "Natural (human alpha-numeric) sort in Microsoft SQL 2005" with a possible answer, but it uses various library functions, as does "Sorting Strings for Humans with IComparer". Below is a test case that currently fails: #include <set> #include <iterator> #include <iostream> #include <vector> #include <cassert> template <typename T> struct LexicographicSort { inline bool operator() (const T& lhs, const T& rhs) const{ std::ostringstream s1,s2; s1 << toLower(lhs); s2 << toLower(rhs); bool less = s1.str() < s2.str(); std::cout<<s1.str()<<" "<<s2.str()<<" "<<less<<"\n"; return less; } inline std::string toLower(const std::string& str) const { std::string newString(""); for (std::string::const_iterator charIt = str.begin(); charIt!=str.end();++charIt) { newString.push_back(std::tolower(*charIt)); } return newString; } }; int main(void) { const std::string reference[5] = {"ab","B","c1","c2","c10"}; std::vector<std::string> referenceStrings(&(reference[0]), &(reference[5])); //Insert in reverse order so we know they get sorted std::set<std::string,LexicographicSort<std::string> > strings(referenceStrings.rbegin(), referenceStrings.rend()); std::cout<<"Items:\n"; std::copy(strings.begin(), strings.end(), std::ostream_iterator<std::string>(std::cout, "\n")); std::vector<std::string> sortedStrings(strings.begin(), strings.end()); assert(sortedStrings == referenceStrings); }

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  • Specializing a template on a lambda in C++0x

    - by Tony A.
    I've written a traits class that lets me extract information about the arguments and type of a function or function object in C++0x (tested with gcc 4.5.0). The general case handles function objects: template <typename F> struct function_traits { template <typename R, typename... A> struct _internal { }; template <typename R, typename... A> struct _internal<R (F::*)(A...)> { // ... }; typedef typename _internal<decltype(&F::operator())>::<<nested types go here>>; }; Then I have a specialization for plain functions at global scope: template <typename R, typename... A> struct function_traits<R (*)(A...)> { // ... }; This works fine, I can pass a function into the template or a function object and it works properly: template <typename F> void foo(F f) { typename function_traits<F>::whatever ...; } int f(int x) { ... } foo(f); What if, instead of passing a function or function object into foo, I want to pass a lambda expression? foo([](int x) { ... }); The problem here is that neither specialization of function_traits<> applies. The C++0x draft says that the type of the expression is a "unique, unnamed, non-union class type". Demangling the result of calling typeid(...).name() on the expression gives me what appears to be gcc's internal naming convention for the lambda, main::{lambda(int)#1}, not something that syntactically represents a C++ typename. In short, is there anything I can put into the template here: template <typename R, typename... A> struct function_traits<????> { ... } that will allow this traits class to accept a lambda expression?

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  • Ruby/Rails - Add records to an object with each loop iteration / Object vs Arrays

    - by ChrisWesAllen
    I'm trying to figure out how to add records to an existing object for each iteration of a loop. I'm having a hard time discovering the difference between an object and an array. I have this @events = Event.find(1) @loops = Choices.find(:all, :limit => 5) #so loop for 5 instances of choice model for loop in @loops @events = Event.find(:all,:conditions => ["event.id = ?", loop.event_id ]) end I'm trying to add a new events to the existing @events object based on the id of whatever the loop variable is. But the ( = ) operator just creates a new instance of the @events object. I tried ( += ) and ( << ) as operators but got the error "You have a nil object when you didn't expect it! You might have expected an instance of Array. The error occurred while evaluating nil" I tried created an array events = [] events << Event.find(1) @loops = Choices.find(:all, :limit => 5) #so loop for 5 instances of choice model for loop in @loops events << Event.find(:all,:conditions => ["event.id = ?", loop.event_id ]) end But I dont know how to call that arrays attributes within the view With objects I was able do create a loop within the view and call all the attributes of that object as well... <table> <% for event in @events %> <tr> <td><%= link_to event.title, event %></td> <td><%= event.start_date %></td> <td><%= event.price %></td> </tr> <% end %> </table> How could i do this with an array set? So the questions are 1) Whats the difference between arrays and objects? 2) Is there a way to add into the existing object for each iteration? 3) If I use an array, is there a way to call the attributes for each array record within the view?

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  • stxxl Assertion `it != root_node_.end()' failed

    - by Fabrizio Silvestri
    I am receiving this assertion failed error when trying to insert an element in a stxxl map. The entire assertion error is the following: resCache: /usr/include/stxxl/bits/containers/btree/btree.h:470: std::pair , bool stxxl::btree::btree::insert(const value_type&) [with KeyType = e_my_key, DataType = unsigned int, CompareType = comp_type, unsigned int RawNodeSize = 16384u, unsigned int RawLeafSize = 131072u, PDAllocStrategy = stxxl::SR, stxxl::btree::btree::value_type = std::pair]: Assertion `it != root_node_.end()' failed. Aborted Any idea? Edit: Here's the code fragment void request_handler::handle_request(my_key& query, reply& rep) { c_++; strip(query.content); std::cout << "Received query " << query.content << " by thread " << boost::this_thread::get_id() << ". It is number " << c_ << "\n"; strcpy(element.first.content, query.content); element.second = c_; testcache_.insert(element); STXXL_MSG("Records in map: " << testcache_.size()); } Edit2 here's more details (I omit constants, e.g. MAX_QUERY_LEN) struct comp_type : std::binary_function<my_key, my_key, bool> { bool operator () (const my_key & a, const my_key & b) const { return strncmp(a.content, b.content, MAX_QUERY_LEN) < 0; } static my_key max_value() { return max_key; } static my_key min_value() { return min_key; } }; typedef stxxl::map<my_key, my_data, comp_type> cacheType; cacheType testcache_; request_handler::request_handler() :testcache_(NODE_CACHE_SIZE, LEAF_CACHE_SIZE) { c_ = 0; memset(max_key.content, (std::numeric_limits<unsigned char>::max)(), MAX_QUERY_LEN); memset(min_key.content, (std::numeric_limits<unsigned char>::min)(), MAX_QUERY_LEN); testcache_.enable_prefetching(); STXXL_MSG("Records in map: " << testcache_.size()); }

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  • JAXB doesn't unmarshal list of interfaces

    - by Joker_vD
    It seems JAXB can't read what it writes. Consider the following code: interface IFoo { void jump(); } @XmlRootElement class Bar implements IFoo { @XmlElement public String y; public Bar() { y = ""; } public Bar(String y) { this.y = y; } @Override public void jump() { System.out.println(y); } } @XmlRootElement class Baz implements IFoo { @XmlElement public int x; public Baz() { x = 0; } public Baz(int x) { this.x = x; } @Override public void jump() { System.out.println(x); } } @XmlRootElement public class Holder { private List<IFoo> things; public Holder() { things = new ArrayList<>(); } @XmlElementWrapper @XmlAnyElement public List<IFoo> getThings() { return things; } public void addThing(IFoo thing) { things.add(thing); } } // ... try { JAXBContext context = JAXBContext.newInstance(Holder.class, Bar.class, Baz.class); Holder holder = new Holder(); holder.addThing(new Bar("1")); holder.addThing(new Baz(2)); holder.addThing(new Baz(3)); for (IFoo thing : holder.getThings()) { thing.jump(); } StringWriter s = new StringWriter(); context.createMarshaller().marshal(holder, s); String data = s.toString(); System.out.println(data); StringReader t = new StringReader(data); Holder holder2 = (Holder)context.createUnmarshaller().unmarshal(t); for (IFoo thing : holder2.getThings()) { thing.jump(); } } catch (Exception e) { System.err.println(e.getMessage()); } It's a simplified example, of course. The point is that I have to store two very differently implemented classes, Bar and Baz, in one collection. Well, I observed that they have pretty similar public interface, so I created an interface IFoo and made them two to implement it. Now, I want to have tools to save and load this collection to/from XML. Unfortunately, this code doesn't quite work: the collection is saved, but then it cannot be loaded! The intended output is 1 2 3 some xml 1 2 3 But unfortunately, the actual output is 1 2 3 some xml com.sun.org.apache.xerces.internal.dom.ElementNSImpl cannot be cast to testapplication1.IFoo Apparently, I need to use the annotations in a different way? Or to give up on JAXB and look for something else? I, well, can write "XMLNode toXML()" method for all classes I wan't to (de)marshal, but...

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  • creating an array of objects in c++

    - by tim22
    I'm trying to create an array of objects in c++. I'm creating a employee object, from my constructor in my company class here: employee obj(int tempIdNum, double tempBase, double tempSales, double tempRate); emp[tempcount]=obj; (this doesn't work?) Emp is the name of the array which is defined here, located in my company h file. Employee emp[4]; more code: Company::Company(string name, string fileName){ string str; int tempcount; int tempIdnum; double tempBase; double tempSales; double tempRate; double num; double arr[16]; this->name=name; //Commission temp; ifstream readFile; readFile.open("fileName"); int inc=0; while(tempcount<4){ for(int i=0+inc; i<4+inc; i++){ readFile>>num; arr[i-inc]=num; } tempIdnum=(int)(arr[0]); tempBase=arr[1]; tempSales=arr[2]; tempRate=arr[3]; Employee obj(int tempIdNum, double tempBase, double tempSales, double tempRate); emp[tempcount]=obj; inc+=4; tempcount++; } readFile.close(); } Here is some more from my h file #include <string> include "Commission.h" using namespace std; ifndef Company_H define Company_H class Company{ private: string name; //name of company Employee emp[4]; //array of payrool info about 4 commission employees int numEmp; //number of employees public: Company(); Company(string name, string fileName); ~Company(); string getName(); Commission getEmployee(int element); int getNumEmp(); }; endif enter code here Does not compile: 46 E:\exercise2\Company.cpp no match for 'operator=' in '((Company*)this)-Company::emp[tempcount] = obj'

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