Tutorial by Examples: i

In comparison to regular classes – case classes notation provides several benefits: All constructor arguments are public and can be accessed on initialized objects (normally this is not the case, as demonstrated here): case class Dog1(age: Int) val x = Dog1(18) println(x.age) // 18 (success!...

[^0-9a-zA-Z] This will match all characters that are neither numbers nor letters (alphanumerical characters). If the underscore character _ is also to be negated, the expression can be shortened to: [^\w] Or: \W In the following sentences: Hi, what's up? I can't wait for 2017!...

[^0-9] This will match all characters that are not ASCII digits. If Unicode digits are also to be negated, the following expression can be used, depending on your flavor/language settings: [^\d] This can be shortened to: \D You may need to enable Unicode character properties support expl...

To get version 5394 use: svn co --revision r5394 https://svn.example.com/svn/MyRepo/MyProject/trunk Or the shorter version: svn co -r 5394 https://svn.example.com/svn/MyRepo/MyProject/trunk Or by using pegged revisions: svn co https://svn.example.com/svn/MyRepo/MyProject/trunk@5394 If al...

Dynamic scoping means that variable lookups occur in the scope where a function is called, not where it is defined. $ x=3 $ func1 () { echo "in func1: $x"; } $ func2 () { local x=9; func1; } $ func2 in func1: 9 $ func1 in func1: 3 In a lexically scoped language, func1 would alway...

If you have an instance of a generic type but for some reason don't know the specific type, you might want to determine the generic arguments that were used to create this instance. Let's say someone created an instance of List<T> like that and passes it to a method: var myList = new List&lt...

Suppose we want to receive a function as a parameter, we can do it like this: function foo(otherFunc: Function): void { ... } If we want to receive a constructor as a parameter: function foo(constructorFunc: { new() }) { new constructorFunc(); } function foo(constructorWithParams...

local Class = {} -- objects and classes will be tables local __meta = {__index = Class} -- ^ if an instance doesn't have a field, try indexing the class function Class.new() -- return setmetatable({}, __meta) -- this is shorter and equivalent to: local new_instance = {} setmetatabl...

The internal keyword is an access modifier for types and type members. Internal types or members are accessible only within files in the same assembly usage: public class BaseClass { // Only accessible within the same assembly internal static int x = 0; } The difference between dif...

The type constructor for lists in the Haskell Prelude is []. The type declaration for a list holding values of type Int is written as follows: xs :: [Int] -- or equivalently, but less conveniently, xs :: [] Int Lists in Haskell are homogeneous sequences, which is to say that all elements mus...

To process lists, we can simply pattern match on the constructors of the list type: listSum :: [Int] -> Int listSum [] = 0 listSum (x:xs) = x + listSum xs We can match more values by specifying a more elaborate pattern: sumTwoPer :: [Int] -> Int sumTwoPer [] = 0 sumTwoPer (x1...

pip doesn't current contain a flag to allow a user to update all outdated packages in one shot. However, this can be accomplished by piping commands together in a Linux environment: pip list --outdated --local | grep -v '^\-e' | cut -d = -f 1 | xargs -n1 pip install -U This command takes all pa...

pip doesn't current contain a flag to allow a user to update all outdated packages in one shot. However, this can be accomplished by piping commands together in a Windows environment: for /F "delims= " %i in ('pip list --outdated --local') do pip install -U %i This command takes all pa...

pip assists in creating requirements.txt files by providing the freeze option. pip freeze > requirements.txt This will save a list of all packages and their version installed on the system to a file named requirements.txt in the current folder.

pip assists in creating requirements.txt files by providing the freeze option. pip freeze --local > requirements.txt The --local parameter will only output a list of packages and versions that are installed locally to a virtualenv. Global packages will not be listed.

Class composition allows explicit relations between objects. In this example, people live in cities that belong to countries. Composition allows people to access the number of all people living in their country: class Country(object): def __init__(self): self.cities=[] ...

Access the nth element of a list (zero-based): list = [1 .. 10] firstElement = list !! 0 -- 1 Note that !! is a partial function, so certain inputs produce errors: list !! (-1) -- *** Exception: Prelude.!!: negative index list !! 1000 -- *** Exception: Prelude.!!: inde...

To make artisan migrate a fresh database before running tests, use DatabaseMigrations. Also if you want to avoid middleware like Auth, use WithoutMiddleware. <?php use Illuminate\Foundation\Testing\WithoutMiddleware; use Illuminate\Foundation\Testing\DatabaseMigrations; class ExampleTest ...

The steps of overload resolution are: Find candidate functions via name lookup. Unqualified calls will perform both regular unqualified lookup as well as argument-dependent lookup (if applicable). Filter the set of candidate functions to a set of viable functions. A viable function for whi...

really_neat.info name = Really Neat Module description = Provides a really neat page for your site core = 7.x really_neat.module <?php /** * @file * Hook implementation and shared functions for the Really Neat Module. */ /** * Implements hook_menu(). */ function really_nea...