Tutorial by Examples: v

Learning the parameters of a prediction function and testing it on the same data is a methodological mistake: a model that would just repeat the labels of the samples that it has just seen would have a perfect score but would fail to predict anything useful on yet-unseen data. This situation is call...

Any nullable type is a generic type. And any nullable type is a value type. There are some tricks which allow to effectively use the result of the Nullable.GetUnderlyingType method when creating code related to reflection/code-generation purposes: public static class TypesHelper { public stat...

C-style bit-manipulation template <typename T> T rightmostSetBitRemoved(T n) { // static_assert(std::is_integral<T>::value && !std::is_signed<T>::value, "type should be unsigned"); // For c++11 and later return n & (n - 1); } Explanation if...

You can check if a variable has been defined in a scope by using ColdFusion's built in StructKeyExists() function. This can be used inside a <cfif> tag to prevent error messages in the event you attempt to refer to a variable that does not exist. You can also use this function to determine whe...

Lists Lists can be defined as: data List a = Nil | Cons a (List a) If we translate this into our type algebra, we get List(a) = 1 + a * List(a) But we can now substitute List(a) again in this expression multiple times, in order to get: List(a) = 1 + a + a*a + a*a*a + a*a*a*a + ... ...

The derivative of a type is the type of its type of one-hole contexts. This is the type that we would get if we make a type variable disappear in every possible point and sum the results. As an example, we can take the triple type (a,a,a), and derive it, obtaining data OneHoleContextsOfTriple = (a...

A function template can be overloaded under the rules for non-template function overloading (same name, but different parameter types) and in addition to that, the overloading is valid if The return type is different, or The template parameter list is different, except for the naming of paramete...

This is a very basic feature selection technique. Its underlying idea is that if a feature is constant (i.e. it has 0 variance), then it cannot be used for finding any interesting patterns and can be removed from the dataset. Consequently, a heuristic approach to feature elimination is to first re...

A simple EntitySystem that processes a Family of entities not once per frame, but after a given interval. Entity processing logic should be placed in processEntity(Entity). For more info, please see IntervalIteratingSystem In the below code example, the best usage for this is the physics world ...

As far as client-side JavaScript engines are concerned (those running inside a browser), there is no straightforward solution available for requesting content from sources other than the current domain. (By the way, this limitation does not exist in JavaScript-server tools such as Node JS.) However...

Create Dynamic Web project, provide following information's as stated below Project name : DemoSpringMVCProject Target runtime : set as Apache Tomcat v7.0 server Click on finish, successfully we have created dynamic web project. Now we have to setup Spring-MVC framework : Create web.xml...

This is a relatively common mistake: You created an rect element, in a bar chart for instance, and you want to add a text label (let's say, the value of that bar). So, using the same variable that you used to append the rect and define its x and y position, you append your text element. Very logic, ...

$ pwd /home/bob/somedir1/somedir2/somedir3 $ pushd /home/bob/otherdir1/otherdir2 /home/bob/otherdir1/otherdir2 /home/bob/somedir1/somedir2/somedir3 $ popd /home/bob/somedir1/somedir2/somedir3 $ pushd /usr /usr /home/bob/somedir1/somedir2/somedir3 $ pushd /var /var /usr /home/bob/som...

In this question, @Viclib asked about using rewrite rules to exploit typeclass laws to eliminate some overloaded function calls: Mind the following class: class ListIsomorphic l where toList :: l a -> [a] fromList :: [a] -> l a I also demand that toList . fromList == id. H...

Inverts the order of the elements in a sequence. If there is no items throws a ArgumentNullException: source is null. Example: // Create an array. int[] array = { 1, 2, 3, 4 }; //Output: // Call reverse extension method on the array. //4 var reverse = array.R...

The div is a block-level element, i.e it occupies the whole of the page width and the siblings are place one below the other irrespective of their width. <div> <p>This is DIV 1</p> </div> <div> <p>This is DIV 2</p> </div> The output of...

Makes an ajax request and updates only part of the view. Bean.java @ManagedBean @ViewScoped public class Bean { public Date getCurrentDate() { return new Date(); } } sample.xhtml <html xmlns="http://www.w3.org/1999/xhtml" xmlns:h="http://xmlns...

The date is updated whenever user types on the input field: Bean.java @ManagedBean @ViewScoped public class Bean { public Date getCurrentDate(){ return new Date(); } } sample.xhtml <html xmlns="http://www.w3.org/1999/xhtml" xmlns:h="http://x...

Some devices connected through a serial port send data to your program at a constant rate (streaming data) or send data at unpredictable intervals. You can configure the serial port to execute a function automatically to handle data whenever it arrives. This is called the "callback function&quo...

Set a convenience method in your base model namespace Base; class Model extends \Phalcon\Mvc\Model { public function sanitize($attr, $filterName) { $filter = $this->getDI()->get('filter'); $this->$attr = $filter->sanitize($this->$attr, $filterName); ...