Tutorial by Examples: a

If we want to test JavaScript on a website, we'll need to use something a bit more powerful than Goutte (which is just cURL via Guzzle). There are a couple of options such as ZombieJS, Selenium and Sahi. For this example I'll use Selenium. First you'll need to install the drivers for Mink: $ compo...

From documentation: The HttpContext.Items collection is the best location to store data that is only needed while processing a given request. Its contents are discarded after each request. It is best used as a means of communicating between components or middleware that operate at different poi...

Django 1.10 introduced a new middleware style where process_request and process_response are merged together. In this new style, a middleware is a callable that returns another callable. Well, actually the former is a middleware factory and the latter is the actual middleware. The middleware facto...

DateTimeField is used to store date time values. class MyModel(models.Model): start_time = models.DateFimeField(null=True, blank=True) created_on = models.DateTimeField(auto_now_add=True) updated_on = models.DateTimeField(auto_now=True) A DateTimeField has two optional parameters:...

A global RegExp match can be performed using preg_match_all. preg_match_all returns all matching results in the subject string (in contrast to preg_match, which only returns the first one). The preg_match_all function returns the number of matches. Third parameter $matches will contain matches in f...

The predicate function matches can be used to evaluate strings on the fly without use of any object declarations. IF matches( val = 'Not a hex string' regex = '[0-9a-f]*' ). cl_demo_output=>display( 'This will not display' ). ELSEIF matches( val = '6c6f7665' reg...

As already pointed out in other pitfalls, catching all exceptions by using try { // Some code } catch (Exception) { // Some error handling } Comes with a lot of different problems. But one perticular problem is that it can lead to deadlocks as it breaks the interrupt system when writ...

The latest version of the Oracle Java style guide mandates that the "then" and "else" statements in an if statement should always be enclosed in "braces" or "curly brackets". Similar rules apply to the bodies of various loop statements. if (a) { //...

Create blank Multi-Device (Firemonkey) application. Drop Rectangle on Form. In Object inspector window (F11) find RotationAngle click on drop down button, and select "Create New TFloatAnimation". Object inspector window is automatically switched to a newly added TFloatAnimation, you...

Scaling to fit Means that the whole image will be visible but there may be some empty space on the sides or top and bottom if the image is not the same aspect as the canvas. The example shows the image scaled to fit. The blue on the sides is due to the fact that the image is not the same aspect as ...

Documenting your work Remember what you've done and retain long outputs which can't be kept in WinDbg's buffer. It's always good to have a log available for reproducing debugging steps, e.g. to ask questions on Stack Overflow. CommandPurpose.logopencreate a log file.logcloseclose the log file.dump...

Following are the Prerequisites for installing Cookiecutter: pip virtualenv PostgreSQL Create a virtualenv for your project and activate it: $ mkvirtualenv <virtualenv name> $ workon <virtualenv name> Now install Cookiecutter using: $ pip install cookiecutter Change dire...

Unlike most other JavaScript objects, symbols are not automatically converted into a string when performing concatenation. let apple = Symbol('Apple') + ''; // throws TypeError! Instead, they have to be explicitly converted into a string when necessary, (for example, to get a textual description...

Server-Side JavaScript Native JSON Samplestack Sample Application Temporal Documents REST Management API Improvements More Semantics Features, Including SPARQL 1.1, Inferencing, and SPARQL UPDATE Node.js Client API REST and Java Client API Improvements Enhanced HTTP Server Features Flexi...

The Symbol.for method allows you to register and look up global symbols by name. The first time it is called with a given key, it creates a new symbol and adds it to the registry. let a = Symbol.for('A'); The next time you call Symbol.for('A'), the same symbol will be returned instead of a new o...

For more complex applications, flat execution profiles may be difficult to follow. This is why many profiling tools also generate some form of annotated callgraph information. gperf2dot converts text output from many profilers (Linux perf, callgrind, oprofile etc.) into a callgraph diagram. You can...

Google Perf Tools also provides a CPU profiler, with a slightly friendlier interface. To use it: Install Google Perf Tools Compile your code as usual Add the libprofiler profiler library to your library load path at runtime Use pprof to generate a flat execution profile, or a callgraph diagram...

The | can be used to have a single case statement match against multiple inputs to yield the same result: def f(str: String): String = str match { case "foo" | "bar" => "Matched!" case _ => "No match." } f("foo") // res0: String = M...

Given the following List of tuples: val pastries = List(("Chocolate Cupcake", 2.50), ("Vanilla Cupcake", 2.25), ("Plain Muffin", 3.25)) Pattern matching can be used to handle each element differently: pastries foreach { pa...

This is an example of an implementation of the identity monad in JavaScript, and could serve as a starting point to create other monads. Based on the conference by Douglas Crockford on monads and gonads Using this approach reusing your functions will be easier because of the flexibility this monad...