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By adding the following extension to array indices can be accessed without knowing if the index is inside bounds. extension Array { subscript (safe index: Int) -> Element? { return indices ~= index ? self[index] : nil } } example: if let thirdValue = array[safe: 2] { ...

Due to very specific way of actor instantiation, injecting dependencies into an actor instance is not trivial. In order to intervene in actor instantiation and allow Spring to inject dependencies one should implement a couple of akka extensions. First of those is an IndirectActorProducer: import ak...

Labeling the alternatives inside a rule starting with the # operator tells ANTLR to generate listener methods for each label corresponding to the alternative. By specifying a label for each alternative in the following rule: // Rule type : int #typeInt | short #typeShort | long ...

#demo-element { background: @theme-color; color: contrast(@theme-color, black, white, 50%); } @theme-color: red; The above example will set the text color of the element as white if the background-color is dark and vice-versa. This is achieved using the contrast() color operation functi...

Due to the vulnerability caused by CSRF, it is generally considered a good practice to check for an AntiForgeryToken on all HttpPosts unless there is a good reason to not do it (some technical issue with the post, there is another authentication mechanism and/or the post does not mutate state like s...

For a 12hour time format one can use: ^(?:0?[0-9]|1[0-2])[-:][0-5][0-9]\s*[ap]m$ Where (?:0?[0-9]|1[0-2]) is the hour [-:] is the separator, which can be adjusted to fit your need [0-5][0-9] is the minute \s*[ap]m followed any number of whitespace characters, and am or pm If you need th...

PresenceOf - Validates that a value is not null or empty string $validator->add('name', new \Phalcon\Validation\Validator\PresenceOf([ 'message' => 'The name is required' ])); Email - Checks if a value has a correct e-mail format $validator->add('email', new \Phalcon\Validation\Va...

In Tcl, a control structure is basically just another command. This is one possible implementation of a do ... while / do ... until control structure. proc do {body keyword expression} { uplevel 1 $body switch $keyword { while {uplevel 1 [list while $expression $body]} u...

In Object oriented programming language, a mixin is a class that contains methods for use by other classes without having to be the parent class of those other classes. How those other classes gain access to the mixin's methods depends on the language. It provides a mechanism for multiple inheritan...

VB 14.0 introduces the ability to add comments after implicit line continuation. Dim number = From c As Char 'Comment In "dj58kwd92n4" 'Comment Where Char.IsNumber(c) 'Comment Select c 'Comment

Use the task dependencies. Depending on how your modules are set up, it may be either ./gradlew dependencies or to see the dependencies of module app use ./gradlew :app:dependencies The example following build.gradle file dependencies { compile 'com.android.support:design:23.2.1' compile...

To create mixins, simply declare lightweight classes that can be used as "behaviours". class Flies { fly() { alert('Is it a bird? Is it a plane?'); } } class Climbs { climb() { alert('My spider-sense is tingling.'); } } class Bulletproof { ...

Using the System.String.Replace method, you can replace part of a string with another string. string s = "Hello World"; s = s.Replace("World", "Universe"); // s = "Hello Universe" All the occurrences of the search string are replaced. This method can al...

The System.String class supports a number of methods to convert between uppercase and lowercase characters in a string. System.String.ToLowerInvariant is used to return a String object converted to lowercase. System.String.ToUpperInvariant is used to return a String object converted to upper...

The System.String.Join method allows to concatenate all elements in a string array, using a specified separator between each element: string[] words = {"One", "Two", "Three", "Four"}; string singleString = String.Join(",", words); // singleString =...

String Concatenation can be done by using the System.String.Concat method, or (much easier) using the + operator: string first = "Hello "; string second = "World"; string concat = first + second; // concat = "Hello World" concat = String.Concat(first, second); // ...

Configure profiling for a project via stack. First build the project with the --profile flag: stack build --profile GHC flags are not required in the cabal file for this to work (like -prof). stack will automatically turn on profiling for both the library and executables in the project. The next...

To find out what packages your project directly depends on, you can simply use this command: stack list-dependencies This way you can find out what version of your dependencies where actually pulled down by stack. Haskell projects frequently find themselves pulling in a lot of libraries indirec...

Add the following code to the onCreate()/onResume() method: SensorManager sensorManager; Sensor mAccelerometer; final float movementThreshold = 0.5f; // You may have to change this value. boolean isMoving = false; float[] prevValues = {1.0f, 1.0f, 1.0f}; float[] currValues = new float[3]; ...

Consider the following code as an illustration: public String joinWords(List<String> words) { String message = ""; for (String word : words) { message = message + " " + word; } return message; } Unfortunate this code is inefficient if the w...