Tutorial by Examples: g

We can use partial application to "lock" the first argument. After applying one argument we are left with a function which expects one more argument before returning the result. (+) :: Int -> Int -> Int addOne :: Int -> Int addOne = (+) 1 We can then use addOne in order to...

Returning partially applied functions is one technique to write concise code. add :: Int -> Int -> Int add x = (+x) add 5 2 In this example (+x) is a partially applied function. Notice that the second parameter to the add function does not need to be specified in the function definitio...

For Addition "4" + 2 # Gives "42" 4 + "2" # Gives 6 1,2,3 + "Hello" # Gives 1,2,3,"Hello" "Hello" + 1,2,3 # Gives "Hello1 2 3" For Multiplication "3" * 2 # Gives "33" 2 * "3&quot...

If a type wishes to have value semantics, and it needs to store objects that are dynamically allocated, then on copy operations, the type will need to allocate new copies of those objects. It must also do this for copy assignment. This kind of copying is called a "deep copy". It effective...

beacon = CLBeaconRegion(proximityUUID: <#NSUUID#>, major: <#CLBeaconMajorValue#>, identifier: <#String#>) // listening to all beacons with given UUID and major value beacon = CLBeaconRegion(proximityUUID: <##NSUUID#>, major: <##CLBeaconMajorValue#>, minor: <##C...

Sometimes two arrays of the same length need to be iterated together, for example: $people = ['Tim', 'Tony', 'Turanga']; $foods = ['chicken', 'beef', 'slurm']; array_map is the simplest way to accomplish this: array_map(function($person, $food) { return "$person likes $food\n"; ...

Swift class FooViewController: UIViewController { override func loadView() { view = FooView() } }

To install packages directly from GitHub use the devtools package: library(devtools) install_github("authorName/repositoryName") To install ggplot2 from github: devtools::install_github("tidyverse/ggplot2") The above command will install the version of ggplot2 that corre...

Once the Symfony Installer is available, create your first Symfony application with the new command: # Linux, Mac OS X $ symfony new my_project_name # Windows c:\> cd projects/ c:\projects\> php symfony new my_project_name This command can be run from anywhere, not necessarily from t...

The installer requires PHP 5.4 or higher. If you still use the legacy PHP 5.3 version, you cannot use the Symfony Installer. Read the Creating Symfony Applications without the Installer section to learn how to proceed. - source: http://symfony.com/doc/current/book/installation.html

In case your project needs to be based on a specific Symfony version, use the optional second argument of the new command: # use the most recent version in any Symfony branch $ symfony new my_project_name 2.8 $ symfony new my_project_name 3.1 # use a specific Symfony version $ symfony new my_...

Given any value of type Int or Long to render a human readable string: fun Long.humanReadable(): String { if (this <= 0) return "0" val units = arrayOf("B", "KB", "MB", "GB", "TB", "EB") val digitGroups = (Mat...

A common use case for extension methods is to improve an existing API. Here are examples of adding exist, notExists and deleteRecursively to the Java 7+ Path class: fun Path.exists(): Boolean = Files.exists(this) fun Path.notExists(): Boolean = !this.exists() fun Path.deleteRecursively(): Bool...

In Kotlin you could write code like: val x: Path = Paths.get("dirName").apply { if (Files.notExists(this)) throw IllegalStateException("The important file does not exist") } But the use of apply is not that clear as to your intent. Sometimes it is clearer to create a ...

With this declaration: fun Temporal.toIsoString(): String = DateTimeFormatter.ISO_INSTANT.format(this) You can now simply: val dateAsString = someInstant.toIsoString()

Custom routing provides specialized need of routing to handle specific incoming requests. In order to defining custom routes, keep in mind that the order of routes that you add to the route table is important. public static void RegisterRoutes(RouteCollection routes) { routes.IgnoreRoute(&qu...

For instance, two tables are given, T1 id x y 8 42 1.9 9 30 1.9 T2 id signal 8 55 8 56 8 59 9 57 9 58 9 60 The goal is to get the new table T3: id x y s1 s2 s3 8 42 1.9 55 ...

To get Unix Epoch Time, use the constant timeIntervalSince1970: Swift let date = NSDate() // current date let unixtime = date.timeIntervalSince1970 Objective-C NSDate *date = [NSDate date]; // current date int unixtime = [date timeIntervalSince1970];

Let's say we want to replace only numbers with 2 digits: regular expression will find them with (\d\d) SELECT REGEXP_REPLACE ('2, 5, and 10 are numbers in this example', '(\d\d)', '#') FROM dual; Results in: '2, 5, and # are numbers in this example' If I want to swap parts of the text, I us...

Let's say you have an object like this: var myObject = { name: 'Peter' } Later in your code, you try to access myObject.name and you get George instead of Peter. You start wondering who changed it and where exactly it was changed. There is a way to place a debugger (or something else) on e...