Tutorial by Examples: pt

Functions which return a character vector Base R has two functions for invoking a system command. Both require an additional parameter to capture the output of the system command. system("top -a -b -n 1", intern = TRUE) system2("top", "-a -b -n 1", stdout = TRUE) ...

Virtually all Prolog systems implement tail call optimization (TCO). This means that predicate calls that are in a tail position can be executed in constant stack space if the predicate is deterministic. Tail recursion optimization (TRO) is a special case of tail call optimization.

This example is written with F# in mind but the ideas are applicable in all environments The first rule when optimizing for performance is to not to rely assumption; always Measure and Verify your assumptions. As we are not writing machine code directly it is hard to predict how the compiler an...

Using c# or vb.net code the conversion is even more simple. An output column is needed because we type can not be changed on the fly, alternative is adding an input column on forehand make it ReadWrite. Next code will fill the new column. public override void Input0_ProcessInputRow(Input0Buffer ...

var numbers = [1,2,3,4,5]; var squares = numbers.map(function(x) { return x*x; }); // squares is [1,4,9,16,25]

var arr = [1, 2, 3, 4, 5]; var sum = arr.reduce((prev, curr) => prev + curr); console.log(sum); // Output: 15 You can also specify an initial value var arr = [1, 2, 3, 4, 5]; var sum = arr.reduce(function (previousValue, currentValue, currentIndex, array) { return previousValue + cur...

0.18.0 Model is passed to subscriptions which means that every state change can modify subscriptions. import Html exposing ( Html, div, text, button ) import Html.Events exposing ( onClick ) import Time main : Program Never Model Msg main = Html.program { init = init ,...

If a static constructor throws an exception, it is never retried. The type is unusable for the lifetime of the AppDomain. Any further usages of the type will raise a TypeInitializationException wrapped around the original exception. public class Animal { static Animal() { Consol...

One of the nicest features of flexbox is to allow optimally fitting containers to their parent element. Live demo. HTML: <div class="flex-container"> <div class="flex-item">1</div> <div class="flex-item">2</div> <div class=&q...

In cryptography, encryption is the process of encoding messages or information in such a way that only authorized parties can access it. Source: Encryption - Wikipedia

As with docopt, with [docopt_dispatch] you craft your --help in the __doc__ variable of your entry-point module. There, you call dispatch with the doc string as argument, so it can run the parser over it. That being done, instead of handling manually the arguments (which usually ends up in a high c...

add_action( 'wp_enqueue_scripts', 'enqueue_my_styles_and_scripts' ); /** * Enqueue scripts (or styles) conditionally. * * Load scripts (or stylesheets) specifically for IE. IE10 and above does * not support conditional comments in standards mode. * * @link https://gist.github.com/wpsc...

Vlookup finds some value in the leftmost column of a range and returns a value some number of columns to the right and in the same row. Let's say you want to find the surname of Employee ID 2 from this table: =VLOOKUP(2,$A$2:$C$4,3,0) The value you're retrieving data for is 2 The table you...

This example is about deliberately ignoring or "squashing" exceptions. Or to be more precise, it is about how to catch and handle an exception in a way that ignores it. However, before we describe how to do this, we should first point out that squashing exceptions is generally not the co...

This exception occurs when a collection is modified while iterating over it using methods other than those provided by the iterator object. For example, we have a list of hats and we want to remove all those that have ear flaps: List<IHat> hats = new ArrayList<>(); hats.add(new Ushanka...

It is not possible to directly use static_cast, const_cast, dynamic_cast and reinterpret_cast on std::shared_ptr to retrieve a pointer sharing ownership with the pointer being passed as argument. Instead, the functions std::static_pointer_cast, std::const_pointer_cast, std::dynamic_pointer_cast and ...

To find active ScriptableObjects during runtime, you can use Resources.FindObjectsOfTypeAll(). T[] instances = Resources.FindObjectsOfTypeAll<T>(); Where T is the type of the ScriptableObject instance you're searching. Active means it has been loaded in memory in some form before. This me...

In functional programming languages like F# null values are considered potentially harmful and poor style (non-idiomatic). Consider this C# code: string x = SomeFunction (); int l = x.Length; x.Length will throw if x is null let's add protection: string x = SomeFunction (); int l = x ...

Error handling is important but can make an elegant algorithm into a mess. Railway Oriented Programming (ROP) is used to make error handling elegant and composable. Consider the simple function f: let tryParse s = let b, v = System.Int32.TryParse s if b then Some v else None let f (g : ...

Let's say we want to change main loop, only for specific taxonomy, or post type. Targeting only main loop on book post type archive page. add_action( 'pre_get_posts', 'my_callback_function' ); function my_callback_function( $query ) { if( !$query->is_main_query() || is_admin() ) return;...