Tutorial by Examples: re

To remove an element inside an array, e.g. the element with the index 1. $fruit = array("bananas", "apples", "peaches"); unset($fruit[1]); This will remove the apples from the list, but notice that unset does not change the indexes of the remaining elements. So $fr...

Retrieve and Output a Cookie Named user The value of a cookie can be retrieved using the global variable $_COOKIE. example if we have a cookie named user we can retrieve it like this echo $_COOKIE['user'];

cat < file.txt Output is same as cat file.txt, but it reads the contents of the file from standard input instead of directly from the file. printf "first line\nSecond line\n" | cat -n The echo command before | outputs two lines. The cat command acts on the output to add line num...

One of the most common tasks is retrieving an existing element from the DOM to manipulate. Most commonly these methods are executed on document, because it is the root node, but all these methods work on any HTML element in the tree. They will only return children from the node it is executed on. R...

CREATE TABLE Employees ( Id int NOT NULL, PRIMARY KEY (Id), ... ); This will create the Employees table with 'Id' as its primary key. The primary key can be used to uniquely identify the rows of a table. Only one primary key is allowed per table. A key can also be composed by one...

Many databases allow to make the primary key value automatically increment when a new key is added. This ensures that every key is different. MySQL CREATE TABLE Employees ( Id int NOT NULL AUTO_INCREMENT, PRIMARY KEY (Id) ); PostgreSQL CREATE TABLE Employees ( Id SERIAL PRIMARY...

The class template std::shared_ptr defines a shared pointer that is able to share ownership of an object with other shared pointers. This contrasts to std::unique_ptr which represents exclusive ownership. The sharing behavior is implemented through a technique known as reference counting, where the...

The jQuery function (usually aliased as $) can be used both to select elements and to create new elements. var myLink = $('<a href="http://stackexchange.com"></a>'); You can optionally pass a second argument with element attributes: var myLink = $('<a>', { 'href': 'h...

UIButtons can be initialized in a frame: Swift let button = UIButton(frame: CGRect(x: x, y: y, width: width, height: height) Objective C UIButton *button = [[UIButton alloc] initWithFrame:CGRectMake(x, y, width, height)]; A specific type of UIButton can be created like this: Swift let but...

To get the physical size of the screen (including window chrome and menubar/launcher): var width = window.screen.width, height = window.screen.height;

To get the “available” area of the screen (i.e. not including any bars on the edges of the screen, but including window chrome and other windows: var availableArea = { pos: { x: window.screen.availLeft, y: window.screen.availTop }, size: { width: window.scr...

To determine the color and pixel depths of the screen: var pixelDepth = window.screen.pixelDepth, colorDepth = window.screen.colorDepth;

Create password hashes using password_hash() to use the current industry best-practice standard hash or key derivation. At time of writing, the standard is bcrypt, which means, that PASSWORD_DEFAULT contains the same value as PASSWORD_BCRYPT. $options = [ 'cost' => 12, ]; $hashedPasswor...

Spoilers are used to hide text or images that would otherwise negatively impact another user's experience. They can be created using >! >!This is hidden until your cursor hovers on top of it This is hidden until your cursor hovers on top of it Note: This is not part of standard markup...

Markdown tables are physically represented using dash - for to separate the header row from the content ones and pipe | for columns. ColumnColumnCellCell is produced by Column | Column ------ | ------ Cell | Cell You can also populate a table in any way you want - LetterDigitCharactera4...

Unlike classes, which are passed by reference, structures are passed through copying: first = "Hello" second = first first += " World!" // first == "Hello World!" // second == "Hello" String is a structure, therefore it's copied on assignment. Structu...

Declare a new variable with var, followed by a name, type, and value: var num: Int = 10 Variables can have their values changed: num = 20 // num now equals 20 Unless they're defined with let: let num: Int = 10 // num cannot change Swift infers the type of variable, so you don't always ha...

Lazy stored properties have values that are not calculated until first accessed. This is useful for memory saving when the variable's calculation is computationally expensive. You declare a lazy property with lazy: lazy var veryExpensiveVariable = expensiveMethod() Often it is assigned to a retu...

The following is handy to have in build logs that identifies the build machine, and some parameters; simply make you main task depend on this task to print it before every build. <!-- Print Environment Info --> <target name="environment"> <!-- Get the current ti...

Mathematical operations on values other than numbers return NaN. "a" + 1 "b" * 3 "cde" - "e" [1, 2, 3] * 2 An exception: Single-number arrays. [2] * [3] // Returns 6 Also, remember that the + operator concatenates strings. "a" + "b&...