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• Find records IN BETWEEN Date Range

  - by Muhammad Kashif Nadeem

  Please see attached image I have a table which have FromDate and ToDate. FromDate is start of some event and ToDate is end of taht event. I need to find a record if search criteria is in between range of dates. e.g. If a record has FromDate 2010/15/5 and ToDate 2010/15/25 and my criteria is FromDate 2010/5/18 and ToDate is 2010/5/21 then this record should be in search results becasue this is in the range of 15 to 25. Following is my search query (chunk of) SELECT m.EventId FROM MajorEvents WHERE ( (m.LocationID = @locationID OR @locationID IS NULL) OR M.LocationID IS NULL) AND ( CONVERT(VARCHAR(10),M.EventDateFrom,23) BETWEEN CONVERT(VARCHAR(10),@DateTimeFrom,23) AND CONVERT(VARCHAR(10),@DateTimeTo,23) OR CONVERT(VARCHAR(10),M.EventDateTo,23) BETWEEN CONVERT(VARCHAR(10),@DateTimeFrom,23) AND CONVERT(VARCHAR(10),@DateTimeTo,23) ) If Search Criteria is equal to FromDate or ToDate then results are ok e.g. If search criterai is DateFrom = 2010/5/15 AND DateTo = 2010/5/18 then this record will return becasue Date From is exactly what is DateFrom in db. OR If search criterai is DateFrom = 2010/5/22 AND DateTo = 2010/5/25 then this record will return becasue Date To is exactly what is DateTo in db But if anything in between this range it does not work Thanks for the help.

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• stackoverflow tags and related tags

  - by parminder

  Hi Experts, I am working on a website where a user can add tags to their posted books. It is similar to stackover flow, but I am keeping my tags in differnt table. so here are the tables/class in linq to entities. Books { bookId, Title } Tags { Id Tag } BooksTags { Id BookId TagId } Here are few sample records. Books BookId Title 113421 A 113422 B Tags Id Tag 1 ASP 2 C# 3 CSS 4 VB 5 VB.NET 6 PHP 7 java 8 pascal BooksTags Id BookId TagId 1 113421 1 2 113421 2 3 113421 3 4 113421 4 5 113422 1 6 113422 4 7 113422 8 Question 1 : I need to write something in linq to entities queries which gives me data according to the tags say if I want bookIds where tagid =1 it should return bookid 113421 and 113422 as it exists in both the books, but If I ask data for tags 1 and 2 it should return only book 113421 as that is the only book where both the tags are present. Question 2 : I need tags and their count too to show in related tags, so in first case my related tags class should have following result. RelatedTags Tag Count 2 1 3 1 4 2 8 1 in the second case when two tags are requested the result should be like RelatedTags Tag Count 3 1 4 1 I have get the first thing working by converting a sql query in linqer, but that seems like a hell. so want to know if there is any better idea. I have used dyanmic where clause to include two tags. So if someone can help. It will be much appreciated. Thanks Parminder

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• Creation of Objects: Constructors or Static Factory Methods

  - by Rachel

  I am going through Effective Java and some of my things which I consider as standard are not suggested by the book, for instance creation of object, I was under the impression that constructors are the best way of doing it and books says we should make use of static factory methods, I am not able to few some advantages and so disadvantages and so am asking this question, here are the benefits of using it. Advantages: One advantage of static factory methods is that, unlike constructors, they have names. A second advantage of static factory methods is that, unlike constructors, they are not required to create a new object each time they’re invoked. A third advantage of static factory methods is that, unlike constructors, they can return an object of any subtype of their return type. A fourth advantage of static factory methods is that they reduce the verbosity of creating parameterized type instances. I am not able to understand this advantage and would appreciate if someone can explain this point Disadvantages: The main disadvantage of providing only static factory methods is that classes without public or protected constructors cannot be subclassed. A second disadvantage of static factory methods is that they are not readily distinguishable from other static methods.I am not getting this point and so would really appreciate some explanation. Reference: Effective Java, Joshua Bloch, Edition 2, pg: 5-10 Also, How to decide to use whether to go for Constructor or Static Factory Method for Object Creation ?

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• jquery ajax post not working with .load in codeigniter

  - by bravo

  i wish to .load multiple views result with jquery ajax the original code (js) $(document).ready(function(){ $("#uid").change( function(){ var uid=$("#uid").val(); $.ajax({ type: "POST", url: "<?= site_url('sp_profile/ajax_userdetail') ?>", dataType: "json", data: "uid="+uid, cache:false, success: function(data){ $("#content").html(data); } }); return false; }); }); this return only one result in what if i want to load 3 results like in <div id="content"></div> <div id="content1"></div> <div id="content2"></div> content could be userid content2 could be user first name content3 could be user last name my js should using .load instead of html right? let me know if i'm wrong. success: function(data){ $("#content").load("<?= site_url('sp_profile/ajax_userdetail')?>"); $("#content2").load("<?= site_url('sp_profile/ajax_userdetail')?>"); $("#content3").load("<?= site_url('sp_profile/ajax_userdetail')?>"); } i stuck with this thing for whole day.. please anyone show me the right way to do the controller and js code.

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• Reduce function calls

  - by Curious2learn

  Hello, I profiled my python program and found that the following function was taking too long to run. Perhaps, I can use a different algorithm and make it run faster. However, I have read that I can also possibly increase the speed by reducing function calls, especially when it gets called repeatedly within a loop. I am a python newbie and would like to learn how to do this and see how much faster it can get. Currently, the function is: def potentialActualBuyers(setOfPeople,theCar,price): count=0 for person in setOfPeople: if person.getUtility(theCar) >= price and person.periodCarPurchased==None: count += 1 return count where setOfPeople is a list of person objects. I tried the following: def potentialActualBuyers(setOfPeople,theCar,price): count=0 Utility=person.getUtility for person in setOfPeople: if Utility(theCar) >= price and person.periodCarPurchased==None: count += 1 return count This, however, gives me an error saying local variable 'person' referenced before assignment Any suggestions, how I can reduce function calls or any other changes that can make the code faster. Again, I am a python newbie and even though I may possibly be able to use a better algorithm, it is still worthwhile learning the answer to the above question. Thanks very much.

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• Bootstrap - Typehead on multiple inputs

  - by Clem

  I have two text intputs, both have to run an autocompletion. The site is using Bootstrap, and the « typeahead » component. I have this HTML : <input type="text" class="js_typeahead" data-role="artist" /> <input type="text" class="js_typeahead" data-role="location" /> I'm using the « data-role » attribute (that is sent to the Ajax controller as a $_POST index), in order to determine what kind of data has to be retrieved from the database. The Javascript goes this way : var myTypeahead = $('input.js_typeahead').typeahead({ source: function(query, process){ var data_role; data_role = myTypeahead.attr('data-role'); return $.post('/ajax/typeahead', { query:query,data_role:data_role },function(data){ return process(data.options); }); } }); With PHP, I check what $_POST['data-role'] contains, an run the MySQL query (in this case, a query either on a list of Artists, or a list of Locations). But the problem is the second "typeahead" returns the same values than the first one (list of Artists). I assume it's because the listener is attached to the object « myTypeahead », and this way the "data-role" attribute which is used, will always be the same. I think I could fix it by using something like : data_role = $(this).attr('data-role'); But of course this doesn't work, as it's a different scope. Maybe I'm doing it all wrong, but at least maybe you people could give me a hint. Sorry if this has already been discussed, I actually searched but without success. Thanks in advance, Clem (from France, sorry for my english)

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• Unit Testing Private Method in Resource Managing Class (C++)

  - by BillyONeal

  I previously asked this question under another name but deleted it because I didn't explain it very well. Let's say I have a class which manages a file. Let's say that this class treats the file as having a specific file format, and contains methods to perform operations on this file: class Foo { std::wstring fileName_; public: Foo(const std::wstring& fileName) : fileName_(fileName) { //Construct a Foo here. }; int getChecksum() { //Open the file and read some part of it //Long method to figure out what checksum it is. //Return the checksum. } }; Let's say I'd like to be able to unit test the part of this class that calculates the checksum. Unit testing the parts of the class that load in the file and such is impractical, because to test every part of the getChecksum() method I might need to construct 40 or 50 files! Now lets say I'd like to reuse the checksum method elsewhere in the class. I extract the method so that it now looks like this: class Foo { std::wstring fileName_; static int calculateChecksum(const std::vector<unsigned char> &fileBytes) { //Long method to figure out what checksum it is. } public: Foo(const std::wstring& fileName) : fileName_(fileName) { //Construct a Foo here. }; int getChecksum() { //Open the file and read some part of it return calculateChecksum( something ); } void modifyThisFileSomehow() { //Perform modification int newChecksum = calculateChecksum( something ); //Apply the newChecksum to the file } }; Now I'd like to unit test the calculateChecksum() method because it's easy to test and complicated, and I don't care about unit testing getChecksum() because it's simple and very difficult to test. But I can't test calculateChecksum() directly because it is private. Does anyone know of a solution to this problem?

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• OnSubmit does work right in the Validation plugin in jQuery

  - by novellino

  Hello, I an quite new to jQuery and I have a problem while trying to create a form. I am using the Validation plugin for validate the email (one the form's field). When I click the Submit button I want to call my own function because I want to save the data in an XML file. This is my button: (as I understood the plugin uses "submit" for understand the button) <input type="submit" name="submit" class="submit" id="submit_btn" value="Send"/> and here is the script for the validation: <script type="text/javascript"> $(document).ready(function() { //this is my form $("#contactForm").validate(); /*save the valid data in the xml*/ $(".submit").click(function() { var email = $("input#email").val(); var subject = $("input#subject").val(); var message = $("textarea#message").val(); if (email == "" || !$("#contactForm").valid()) { return false; } var dataString = 'email='+ email + '&subject=' + subject + '&message=' + message; //alert("DATA: " +dataString); $.ajax({ type: "POST", url: "SaveData.jsp", data: dataString, success: function(data){} }); return false; }); }); In general it works ok but I have two basic problems. When I click the button in the beginning having all the form empty, I get no message for the field required. Also when the data are valid and I am doing the submit, the form does not become clear after the submit. If I deleted this script code, these actions are working properly but I can not save the data! Does anyone know what is wrong? Thanks a lot!

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• C++ operator lookup rules / Koenig lookup

  - by John Bartholomew

  While writing a test suite, I needed to provide an implementation of operator<<(std::ostream&... for Boost unit test to use. This worked: namespace theseus { namespace core { std::ostream& operator<<(std::ostream& ss, const PixelRGB& p) { return (ss << "PixelRGB(" << (int)p.r << "," << (int)p.g << "," << (int)p.b << ")"); } }} This didn't: std::ostream& operator<<(std::ostream& ss, const theseus::core::PixelRGB& p) { return (ss << "PixelRGB(" << (int)p.r << "," << (int)p.g << "," << (int)p.b << ")"); } Apparently, the second wasn't included in the candidate matches when g++ tried to resolve the use of the operator. Why (what rule causes this)? The code calling operator<< is deep within the Boost unit test framework, but here's the test code: BOOST_AUTO_TEST_SUITE(core_image) BOOST_AUTO_TEST_CASE(test_output) { using namespace theseus::core; BOOST_TEST_MESSAGE(PixelRGB(5,5,5)); // only compiles with operator<< definition inside theseus::core std::cout << PixelRGB(5,5,5) << "\n"; // works with either definition BOOST_CHECK(true); // prevent no-assertion error } BOOST_AUTO_TEST_SUITE_END() For reference, I'm using g++ 4.4 (though for the moment I'm assuming this behaviour is standards-conformant).

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• Invoking a function (main()) from a binary file in C

  - by Dhara Darji

  I have simple c program like, my_bin.c: #include <stdio.h> int main() { printf("Success!\n"); return 0; } I compile it with gcc and got executable: my_bin. Now I want to invoke main (or run this my_bin) using another C program. That I did with mmap and function pointer like this: #include <stdio.h> #include <fcntl.h> #include <sys/mman.h> int main() { void (*fun)(); int fd; int *map; fd = open("./my_bin", O_RDONLY); map = mmap(0, 8378, PROT_READ, MAP_SHARED, fd, 0); fun = map; fun(); return 0; } PS: I went through some tutorial, for how to read binary file and execute. But this gives Seg fault, any help appreciated! Thanks!

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• Yii CGridView and dropdown filter

  - by Dmitriy Gunchenko

  I created dropdown filter, it's display, but don't worked right. As I anderstand trouble in search() method view: $this->widget('zii.widgets.grid.CGridView', array( 'dataProvider'=>$model->search(), 'filter' => $model, 'columns'=>array( array( 'name' => 'client_id', 'filter' => CHtml::listData(Client::model()->findAll(), 'client_id', 'name'), 'value'=>'$data->client->name' ), 'task' ) )); I have to tables, and they relations are shown down model: public function relations() { // NOTE: you may need to adjust the relation name and the related // class name for the relations automatically generated below. return array( 'client' => array(self::BELONGS_TO, 'Client', 'client_id'), ); } public function search() { // Warning: Please modify the following code to remove attributes that // should not be searched. $criteria=new CDbCriteria; $criteria->with = array('client'); $criteria->compare('task_id',$this->task_id); $criteria->compare('client_id',$this->client_id); $criteria->compare('name',$this->client->name); $criteria->compare('task',$this->task,true); $criteria->compare('start_date',$this->start_date,true); $criteria->compare('end_date',$this->end_date,true); $criteria->compare('complete',$this->complete); return new CActiveDataProvider($this, array( 'criteria'=>$criteria, )); }

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• Why does this extension method throw a NullReferenceException in VB.NET?

  - by Dan

  From previous experience I had been under the impression that it's perfectly legal (though perhaps not advisable) to call extension methods on a null instance. So in C#, this code compiles and runs: // code in static class static bool IsNull(this object obj) { return obj == null; } // code elsewhere object x = null; bool exists = !x.IsNull(); However, I was just putting together a little suite of example code for the other members of my development team (we just upgraded to .NET 3.5 and I've been assigned the task of getting the team up to speed on some of the new features available to us), and I wrote what I thought was the VB.NET equivalent of the above code, only to discover that it actually throws a NullReferenceException. The code I wrote was this: ' code in module ' <Extension()> _ Function IsNull(ByVal obj As Object) As Boolean Return obj Is Nothing End Function ' code elsewhere ' Dim exampleObject As Object = Nothing Dim exists As Boolean = Not exampleObject.IsNull() The debugger stops right there, as if I'd called an instance method. Am I doing something wrong (e.g., is there some subtle difference in the way I defined the extension method between C# and VB.NET)? Is it actually not legal to call an extension method on a null instance in VB.NET, though it's legal in C#? (I would have thought this was a .NET thing as opposed to a language-specific thing, but perhaps I was wrong.) Can anybody explain this one to me?

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• Pass Linq Expression to a function

  - by Kushan Hasithe Fernando

  I want to pass a property list of a class to a function. with in the function based on property list I'm going to generate a query. As exactly same functionality in Linq Select method. Here I'm gonna implement this for Ingress Database. As an example, in front end I wanna run a select as this, My Entity Class is like this public class Customer { [System.Data.Linq.Mapping.ColumnAttribute(Name="Id",IsPrimaryKey=true)] public string Id { get; set; } [System.Data.Linq.Mapping.ColumnAttribute(Name = "Name")] public string Name { get; set; } [System.Data.Linq.Mapping.ColumnAttribute(Name = "Address")] public string Address { get; set; } [System.Data.Linq.Mapping.ColumnAttribute(Name = "Email")] public string Email { get; set; } [System.Data.Linq.Mapping.ColumnAttribute(Name = "Mobile")] public string Mobile { get; set; } } I wanna call a Select function like this, var result = dataAccessService.Select<Customer>(C=>C.Name,C.Address); then,using result I can get the Name and Address properties' values. I think my Select function should looks like this, ( *I think this should done using Linq Expression. But im not sure what are the input parameter and return type. * ) Class DataAccessService { // I'm not sure about this return type and input types, generic types. public TResult Select<TSource,TResult>(Expression<Func<TSource,TResult>> selector) { // Here using the property list, // I can get the ColumnAttribute name value and I can generate a select query. } } This is a attempt to create a functionality like in Linq. But im not an expert in Linq Expressions. There is a project call DbLinq from MIT, but its a big project and still i couldn't grab anything helpful from that. Can someone please help me to start this, or can someone link me some useful resources to read about this.

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• Compilation errors calling find_if using a functor

  - by Jim Wong

  We are having a bit of trouble using find_if to search a vector of pairs for an entry in which the first element of the pair matches a particular value. To make this work, we have defined a trivial functor whose operator() takes a pair as input and compares the first entry against a string. Unfortunately, when we actually add a call to find_if using an instance of our functor constructed using a temporary string value, the compiler produces a raft of error messages. Oddly (to me, anyway), if we replace the temporary with a string that we've created on the stack, things seem to work. Here's what the code (including both versions) looks like: typedef std::pair<std::string, std::string> MyPair; typedef std::vector<MyPair> MyVector; struct MyFunctor: std::unary_function <const MyPair&, bool> { explicit MyFunctor(const std::string& val) : m_val(val) {} bool operator() (const MyPair& p) { return p.first == m_val; } const std::string m_val; }; bool f(const char* s) { MyFunctor f(std::string(s)); // ERROR // std::string str(s); // MyFunctor f(str); // OK MyVector vec; MyVector::const_iterator i = std::find_if(vec.begin(), vec.end(), f); return i != vec.end(); } And here's what the most interesting error message looks like: /usr/include/c++/4.2.1/bits/stl_algo.h:260: error: conversion from ‘std::pair, std::allocator , std::basic_string, std::allocator ’ to non-scalar type ‘std::string’ requested Because we have a workaround, we're mostly curious as to why the first form causes problems. I'm sure we're missing something, but we haven't been able to figure out what it is.

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• javaScript .splice() not working on correctly

  - by adardesign

  I am setting a cookie for each navigation container that is clicked on. It sets an array that is joined and set the cookie value. if its clicked again then its removed from the array. It somehow buggy. It only splices after clicking on other elements. and then it behaves weird. Thanks much. var navLinkToOpen; var setNavCookie = function(value){ var isSet = false; var checkCookies = checkNavCookie() setCookieHelper = checkCookies? checkCookies.split(","): []; console.log("value passed", value) for(i in setCookieHelper){ if(value == setCookieHelper[i]){ setCookieHelper.splice(value,1); isSet = true; } } if(!isSet){ setCookieHelper.push(value) } setCookieHelper.join(",") document.cookie = "navLinkToOpen"+"="+setCookieHelper; } var checkNavCookie = function(){ var allCookies = document.cookie.split( ';' ); for (i = 0; i < allCookies.length; i++ ){ temp = allCookies[i].split("=") if(temp[0].match("navLinkToOpen")){ var getValue = temp[1] } } return getValue || false } $(document).ready(function() { $("#LeftNav li").has("b").addClass("navHeader").not(":first").siblings("li").hide() $(".navHeader").click(function(){ $(this).toggleClass("collapsed").nextUntil("li:has('b')").slideToggle(300); setNavCookie($('.navHeader').index($(this))) return false }) console.log("init",document.cookie) var testCookies = checkNavCookie(); if(testCookies){ finalArrayValue = testCookies.split(",") for(i in finalArrayValue){ $(".navHeader").eq(finalArrayValue[i]).toggleClass("collapsed").nextUntil(".navHeader").slideToggle (0); } } });

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• ContentNegotiatingViewResolver Issue

  - by Jay

  How to map a url of this kind "/myapp/sample" to map to the default MarshallingView instead of a JSTLView. @RequestMapping("/vets") public ModelMap vetsHandler() { Vets vets = new Vets(); vets.getVetList().addAll(this.clinic.getVets()); return new ModelMap(vets); } The above code works fine. When i tried to use http://.../vets.xml, I was able to download the xml. But, @RequestMapping("/myapp/vets") public ModelMap vetsHandler() { Vets vets = new Vets(); vets.getVetList().addAll(this.clinic.getVets()); return new ModelMap(vets); } doesn't resolve to the XML MarshalView, instead it resolves to JSTLView. Any thoughts? below is the spring v 3 configuration from the petclinic example, that i'm using. <bean id="vets" class="org.springframework.web.servlet.view.xml.MarshallingView"> <property name="contentType" value="application/vnd.springsource.samples.petclinic+xml"/> <property name="marshaller" ref="marshaller"/> </bean> <bean id="test" class="org.springframework.web.servlet.view.xml.MarshallingView"> <property name="contentType" value="application/vnd.springsource.samples.petclinic+xml"/> <property name="marshaller" ref="marshaller"/> </bean> <oxm:jaxb2-marshaller id="marshaller"> <oxm:class-to-be-bound name="org.springframework.samples.petclinic.Vets"/> <oxm:class-to-be-bound name="org.springframework.samples.petclinic.Test1"/> </oxm:jaxb2-marshaller>

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• Optimizing a shared buffer in a producer/consumer multithreaded environment

  - by Etan

  I have some project where I have a single producer thread which writes events into a buffer, and an additional single consumer thread which takes events from the buffer. My goal is to optimize this thing for a single machine to achieve maximum throughput. Currently, I am using some simple lock-free ring buffer (lock-free is possible since I have only one consumer and one producer thread and therefore the pointers are only updated by a single thread). #define BUF_SIZE 32768 struct buf_t { volatile int writepos; volatile void * buffer[BUF_SIZE]; volatile int readpos;) }; void produce (buf_t *b, void * e) { int next = (b->writepos+1) % BUF_SIZE; while (b->readpos == next); // queue is full. wait b->buffer[b->writepos] = e; b->writepos = next; } void * consume (buf_t *b) { while (b->readpos == b->writepos); // nothing to consume. wait int next = (b->readpos+1) % BUF_SIZE; void * res = b->buffer[b->readpos]; b->readpos = next; return res; } buf_t *alloc () { buf_t *b = (buf_t *)malloc(sizeof(buf_t)); b->writepos = 0; b->readpos = 0; return b; } However, this implementation is not yet fast enough and should be optimized further. I've tried with different BUF_SIZE values and got some speed-up. Additionaly, I've moved writepos before the buffer and readpos after the buffer to ensure that both variables are on different cache lines which resulted also in some speed. What I need is a speedup of about 400 %. Do you have any ideas how I could achieve this using things like padding etc?

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• Something confusing about FormsOf (Sql server Full-Text searching)

  - by AspOnMyNet

  hi I'm using Sql Server 2008 1) A given <simple_term> within a <generation_term> will not match both nouns and verbs. If I understand the above text correctly, then query SELECT * FROM someTable WHERE CONTAINS ( *, ' FORMSOF ( INFLECTIONAL, park ) ' ) should search for either nouns or verbs derived from the root word “park”, but not for both? Thus out of the two rows, one containing noun parks and other verb parking, the above query should return just one of the two rows? But as it turns out, query returns both rows, so are perhaps my assumptions a bit off or is the above quote wrong?! 2) From Msdn: If freetext_string is enclosed in double quotation marks, a phrase match is instead performed; stemming and thesaurus are not performed. According to the above quote the following query shouldn’t return rows containing strings surfing ( due to query not performing stemming ), surf ( due to query performing phrase matching and not individual word matching ) and surfing with suzy’s sister ( due to query not performing stemming and due to query performing phrase matching and not word matching ), but it does. Thus, it appears that even when *freetext_string* is enclosed in double quotation marks, stemming is still preformed, while phrase matching is not: SELECT * FROM someTable WHERE FREETEXT( *, ' "surf sister" ' ) So is the above quote wrong or...? thanx

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• Concise C# code for gathering several properties with a non-null value into a collection?

  - by stakx

  A fairly basic problem for a change. Given a class such as this: public class X { public T A; public T B; public T C; ... // (other fields, properties, and methods are not of interest here) } I am looking for a concise way to code a method that will return all A, B, C, ... that are not null in an enumerable collection. (Assume that declaring these fields as an array is not an option.) public IEnumerable<T> GetAllNonNullAs(this X x) { // ? } The obvious implementation of this method would be: public IEnumerable<T> GetAllNonNullAs(this X x) { var resultSet = new List<T>(); if (x.A != null) resultSet.Add(x.A); if (x.B != null) resultSet.Add(x.B); if (x.C != null) resultSet.Add(x.C); ... return resultSet; } What's bothering me here in particular is that the code looks verbose and repetitive, and that I don't know the initial List capacity in advance. It's my hope that there is a more clever way, probably something involving the ?? operator? Any ideas?

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• Does "epsilon" really guarantees anything in floating-point computations?!

  - by Michal Czardybon

  To make the problem short let's say I want to compute expression: a / (b - c) on float's. To make sure the result is meaningful, I can check if 'b' and 'c' are inequal: float eps = std::numeric_limits<float>::epsilon(); if ((b - c) > EPS || (c - b) > EPS) { return a / (b - c); } but my tests show it is not enough to guarantee either meaningful results nor not failing to provide a result if it is possible. Case 1: a = 1.0f; b = 0.00000003f; c = 0.00000002f; Result: The if condition is NOT met, but the expression would produce a correct result 100000008 (as for the floats' precision). Case 2: a = 1e33f; b = 0.000003; c = 0.000002; Result: The if condition is met, but the expression produces not a meaningful result +1.#INF00. I found it much more reliable to check the result, not the arguments: const float INF = numeric_limits<float>::infinity(); float x = a / (b - c); if (-INF < x && x < INF) { return x; } But what for is the epsilon then and why is everyone saying epsilon is good to use?

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• Dynamic loading a class in java with a different package name

  - by C. Ross

  Is it possible to load a class in Java and 'fake' the package name/canonical name of a class? I tried doing this, the obvious way, but I get a "class name doesn't match" message in a ClassDefNotFoundException. The reason I'm doing this is I'm trying to load an API that was written in the default package so that I can use it directly without using reflection. The code will compile against the class in a folder structure representing the package and a package name import. ie: ./com/DefaultPackageClass.class // ... import com.DefaultPackageClass; import java.util.Vector; // ... My current code is as follows: public Class loadClass(String name) throws ClassNotFoundException { if(!CLASS_NAME.equals(name)) return super.loadClass(name); try { URL myUrl = new URL(fileUrl); URLConnection connection = myUrl.openConnection(); InputStream input = connection.getInputStream(); ByteArrayOutputStream buffer = new ByteArrayOutputStream(); int data = input.read(); while(data != -1){ buffer.write(data); data = input.read(); } input.close(); byte[] classData = buffer.toByteArray(); return defineClass(CLASS_NAME, classData, 0, classData.length); } catch (MalformedURLException e) { throw new UndeclaredThrowableException(e); } catch (IOException e) { throw new UndeclaredThrowableException(e); } }

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• Why does my javascript file sometimes compressed while sometimes not?(IIS Gzip problem)

  - by Kevin Yang

  i enable gzip for javascript file in my iis settings, here 's the corresponding config section. <httpCompression directory="%SystemDrive%\inetpub\temp\IIS Temporary Compressed Files"> <scheme name="gzip" dll="%Windir%\system32\inetsrv\gzip.dll" staticCompressionLevel="10" dynamicCompressionLevel="8" /> <dynamicTypes> <add mimeType="text/*" enabled="true" /> <add mimeType="message/*" enabled="true" /> <add mimeType="application/soap+msbin1" enabled="true" /> <add mimeType="*/*" enabled="false" /> </dynamicTypes> <staticTypes> <add mimeType="text/*" enabled="true" /> <add mimeType="message/*" enabled="true" /> <add mimeType="application/javascript" enabled="true" /> <add mimeType="application/x-javascript" enabled="true" /> <add mimeType="*/*" enabled="false" /> </staticTypes> </httpCompression> currently, when i download my js file, it seems that sometimes server return the gzip one, and sometimes not. i dont know why, and how to debug that. If a file is already gzipped, it should be cached in local disk, and next time someone visit that file again, iis kernel should return the cache gzip file directly without compressing it again. Is that right?

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• C# iterator is executed twice when composing two IEnumerable methods

  - by achristoph

  I just started learning about C# iterator but got confused with the flow of the program after reading the output of the program. The foreach with uniqueVals seems to be executed twice. My understanding is that the first few lines up to the line before "Nums in Square: 3" should not be there. Can anyone help to explain why this happens? The output is: Unique: 1 Adding to uniqueVals: 1 Unique: 2 Adding to uniqueVals: 2 Unique: 2 Unique: 3 Adding to uniqueVals: 3 Nums in Square: 3 Unique: 1 Adding to uniqueVals: 1 Square: 1 Number returned from Unique: 1 Unique: 2 Adding to uniqueVals: 2 Square: 2 Number returned from Unique: 4 Unique: 2 Unique: 3 Adding to uniqueVals: 3 Square: 3 Number returned from Unique: 9 static class Program { public static IEnumerable<T> Unique<T>(IEnumerable<T> sequence) { Dictionary<T, T> uniqueVals = new Dictionary<T, T>(); foreach (T item in sequence) { Console.WriteLine("Unique: {0}", item); if (!uniqueVals.ContainsKey(item)) { Console.WriteLine("Adding to uniqueVals: {0}", item); uniqueVals.Add(item, item); yield return item; Console.WriteLine("After Unique yield: {0}", item); } } } public static IEnumerable<int> Square(IEnumerable<int> nums) { Console.WriteLine("Nums in Square: {0}", nums.Count()); foreach (int num in nums) { Console.WriteLine("Square: {0}", num); yield return num * num; Console.WriteLine("After Square yield: {0}", num); } } static void Main(string[] args) { var nums = new int[] { 1, 2, 2, 3 }; foreach (int num in Square(Unique(nums))) Console.WriteLine("Number returned from Unique: {0}", num); Console.Read(); } }

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• Drupal Studs help me with my form_alter hook ( I am almost there)

  - by user363036

  So I think I am almost there conceptually but need some missing pointers. Objective is to add a few more fields to the normal user registration form, style it a little, then submit it with storing the extra fields in a table. This is what I have so far. Can someone give me the final nudge and get me going. Please help me. Also how do I apply some minor styling like aligning the new form fields ? Thank you so much !!!!!!!!! function module_menu() { $items = array(); $items['school/registration'] = array( 'title' = 'Upgraded Registration Form', 'page callback' ='module_school_register', 'type' = MENU_CALLBACK ); return $items; }//end of the function function module_school_register(){ return drupal_get_form('form_school_register'); }//end of the function function module_school_form_alter(&$form, $form_state, $form_id) { dsm($form_id); if ($form_id == 'user_registration_form') { // modify the "#submit" form property by prepending another submit handler array $form['#submit'] = array_merge( array('_module_registration_submit' = array()), $form['#submit'] ); } } function _module_registration_submit($form_id, $form_values) { // store extra data in different table } function module_registration_validate($form, &$form_state) { $error=0; //Validation stuff here, set $error to true if something went wrong, or however u want to do this. Completely up to u in how u set errors. if ($error) { form_set_error('new_field_name', 'AHH SOMETHING WRONG!'); } }

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• How to use R's ellipsis feature when writing your own function?

  - by Ryan Thompson

  The R language has a nifty feature for defining functions that can take a variable number of arguments. For example, the function data.frame takes any number of arguments, and each argument becomes the data for a column in the resulting data table. Example usage: > data.frame(letters=c("a", "b", "c"), numbers=c(1,2,3), notes=c("do", "re", "mi")) letters numbers notes 1 a 1 do 2 b 2 re 3 c 3 mi The function's signature includes an ellipsis, like this: function (..., row.names = NULL, check.rows = FALSE, check.names = TRUE, stringsAsFactors = default.stringsAsFactors()) { [FUNCTION DEFINITION HERE] } I would like to write a function that does something similar, taking multiple values and consolidating them into a single return value (as well as doing some other processing). In order to do this, I need to figure out how to "unpack" the ... from the function's arguments within the function. I don't know how to do this. The relevant line in the function definition of data.frame is object <- as.list(substitute(list(...)))[-1L], which I can't make any sense of. So how can I convert the ellipsis from the function's signature into, for example, a list? To be more specific, how can I write get_list_from_ellipsis in the code below? my_ellipsis_function(...) { input_list <- get.list.from.ellipsis(...) output_list <- lapply(X=input_list, FUN=do_something_interesting) return(output_list) } my_ellipsis_function(a=1:10,b=11:20,c=21:30)

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