Tutorial by Examples: nd

A StringBuilder represents a series of characters, which unlike a normal string, are mutable. Often times there is a need to modify strings that we've already made, but the standard string object is not mutable. This means that each time a string is modified, a new string object needs to be created,...

OSX Implement the contract of the role-specific protocol (NSAccessibilityButton, NSAccessibilityImage, NSAccessibilityGroup, etc) within the NSAccessibility protocol that best matches the behavior of the GUI element being rendered. Linux / BSD For GNOME applications, the GNOME Accessibility Impl...

RewriteCond %{REQUEST_FILENAME} !-f RewriteCond %{REQUEST_URI} !(.*)/$ RewriteRule ^(.*)$ /$1/ [L,R=301] The first RewriteCond helps exclude the files. The second RewriteCond checks if there is already a trailing slash. If the case is so RewriteRule is not applied. If you have any URL that s...

Laravel's events allows to implement the Observer pattern. This can be used to send a welcome email to a user whenever they register on your application. New events and listeners can be generated using the artisan command line utility after registering the event and their particular listener in App...

Both #save and #destroy come wrapped in a transaction that ensures that whatever you do in validations or callbacks will happen under its protected cover. So you can use validations to check for values that the transaction depends on or you can raise exceptions in the callbacks to rollback, includin...

The number that follows the associativity information describes in what order the operators are applied. It must always be between 0 and 9 inclusive. This is commonly referred to as how tightly the operator binds. For example, consider the following fixity declarations (in base) infixl 6 + infixl ...

C++11 The type_traits header contains a set of template classes and helpers to transform and check properties of types at compile-time. These traits are typically used in templates to check for user errors, support generic programming, and allow for optimizations. Most type traits are used to c...

Emacs uses the terms point, mark, and region to provide more precision about the selected text and position of the cursor. By understanding these terms, it'll help you understand and use other operations and functions. The point is the place in a buffer where editing (i.e. insertion) is currently t...

Killing and yanking more or less correspond to what is usually called "cutting" and "pasting". Killing killing means deleting text, and copying it to the kill-ring (which could be seen as a sort of "clipboard" in the "cut & paste" terminology). The kill ...

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If the shift count value is a negative value then both left shift and right shift operations are undefined1: int x = 5 << -3; /* undefined */ int x = 5 >> -3; /* undefined */ If left shift is performed on a negative value, it's undefined: int x = -5 << 3; /* undefined */ I...

#Region directive can now be placed inside methods and can even span over methods, classes and modules. #Region "A Region Spanning A Class and Ending Inside Of A Method In A Module" Public Class FakeClass 'Nothing to see here, just a fake class. End Class Module Extensi...

Dynamic Arrays Adding and reducing variables on an array dynamically is a huge advantage for when the information you are treating does not have a set number of variables. Adding Values Dynamically You can simply resize the Array with the ReDim Statement, this will resize the array but to if you ...

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] { ...

#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...

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...

2.1.3 1. Preview Different Devices There is a preview panel at the right of the android studio. In thispanel there is a button with device name with which you are previewing the UI of your app like this . Click on small dropdown indicator of this and a floating panel will appear with all the pr...

In Emacs, basic search tool (I-Search) allows you to search after or before the location of your cursor. To search for sometext after the location of your cursor (search-forward) hit C-s sometext. If you want to go to the next occurence of sometext, just press C-s again (and so on for the ne...

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 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...