Tutorial by Examples: re

Subroutine arguments in Perl are passed by reference, unless they are in the signature. This means that the members of the @_ array inside the sub are just aliases to the actual arguments. In the following example, $text in the main program is left modified after the subroutine call because $_[0] in...

1.7+ Timing out an HTTP request with a context can be accomplished with only the standard library (not the subrepos) in 1.7+: import ( "context" "net/http" "time" ) req, err := http.NewRequest("GET", `https://example.net`, nil) ctx, _ := ...

Mage::app()->getStores(); Returns an array of Mage_Core_Model_Store models.

To get started quickly with Express, you can use the Express generator which will create an application skeleton for you. First, install it globally with npm: npm install express-generator -g You may need to put sudo before this command if you get a "permission denied" error. Once th...

Categories provide the ability to add some extra functionality to an object without subclassing or changing the actual object. For example we want to set some custom fonts. Let's create a category that add functionality to UIFont class. Open your XCode project, click on File -> New -> File a...

There is no simple way to obtain attributes from an interface, since classes does not inherit attributes from an interface. Whenever implementing an interface or overriding members in a derived class, you need to re-declare the attributes. So in the example below output would be True in all three c...

The code below implements a very simple complex number type for which the underlying field is automatically promoted, following the language's type promotion rules, under application of the four basic operators (+, -, *, and /) with a member of a different field (be it another complex<T> or so...

By default, a filter has a single parameter: the variable it is applied on. But you can pass more parameter to the function: angular .module('app', []) .controller('MyController', function($scope) { $scope.example = 0.098152; }) .filter('percentage', function($filter) { return...

Consider the case of creating a nested list structure by multiplying: li = [[]] * 3 print(li) # Out: [[], [], []] At first glance we would think we have a list of containing 3 different nested lists. Let's try to append 1 to the first one: li[0].append(1) print(li) # Out: [[1], [1], [1]] ...

iex> [1, 2, 3] -- [1, 3] [2] -- removes the first occurrence of an item on the left list for each item on the right.

Looping via recursion is also possible in Kotlin as in most programming languages. fun factorial(n: Long): Long = if (n == 0) 1 else n * factorial(n - 1) println(factorial(10)) // 3628800 In the example above, the factorial function will be called repeatedly by itself until the given conditio...

Directives can be used to build reusable components. Here is an example of a "user box" component: userBox.js angular.module('simpleDirective', []).directive('userBox', function() { return { scope: { username: '=username', reputation: '=reputation' }, ...

Preliminary Install the Cordova cli tools, if you haven't already. $ npm install -g cordova Navigate to your desired working folder. $ cd /path/to/coding/folder Creating the application Create a new application $ cordova create <appProjectName> <appNameSpace> <appName> For ...

POSIX/IEEE Open Group Base Specification says: [2addr] s/BRE/replacement/flags Substitute the replacement string for instances of the BRE in the pattern space. Any character other than backslash or newline can be used instead of a slash to delimit the BRE and the replacement. Within the BRE a...

Coming from imperative languages many developers wonder how to write a for-loop that exits early as F# doesn't support break, continue or return. The answer in F# is to use tail-recursion which is a flexible and idiomatic way to iterate while still providing excellent performance. Say we want to ...

The following function is returning another function as its result which can be later assigned to a variable and called: func jediTrainer () -> ((String, Int) -> String) { func train(name: String, times: Int) -> (String) { return "\(name) has been trained in the Force \(times)...

Problem: When you use many labels inside a view, you maybe get a warning: How can we fix this warning? Solution: We calculate and set the priorities in order. The priorities must be different from labels. It means which is important will get higher priority. For example, in my case, I set the ve...

Often data comes in tables. Generally one can divide this tabular data in wide and long formats. In a wide format, each variable has its own column. PersonHeight [cm]Age [yr]Alison17820Bob17445Carl18231 However, sometimes it is more convenient to have a long format, in which all variables are in o...

The degree of parallelism is the maximum number of concurrently executing tasks that will be used to process the query. var sequence = Enumerable.Range(1, 10000); var evenNumbers = sequence.AsParallel() .WithDegreeOfParallelism(4) .Where(x =&gt...

This example shows how PLINQ can be used to calculate the even numbers between 1 and 10,000 using multiple threads. Order will be maintained in the resulting list, however keep in mind that AsOrdered may hurt performance for a large numbers of elements, so un-ordered processing is preferred when pos...