Tutorial by Examples: at

Suppose we want to read and stack a bunch of similarly-formatted files. The quick solution is: rbindlist(lapply(list.files(patt="csv$"), fread), id=TRUE) We might not be satisfied with this for a couple reasons: It might run into errors when reading with fread or when stacking with ...

Specifies custom foreign key name if a foreign key not following EF's convention is desired. public class Person { public int IdAddress { get; set; } [ForeignKey(nameof(IdAddress))] public virtual Address HomeAddress { get; set; } } This can also be used when you have multipl...

Split vector of texts using one pattern: stri_split_fixed(c("To be or not to be.", "This is very short sentence.")," ") # [[1]] # [1] "To" "be" "or" "not" "to" "be." # # [[2]] # [1] "This" ...

/// <summary> /// Read configuration values from app.config and convert to specified types /// </summary> public static class ConfigurationReader { /// <summary> /// Get value from AppSettings by key, convert to Type of default value or typ...

You can wrap values into actions and pipe the result of one computation into another: return :: Monad m => a -> m a (>>=) :: Monad m => m a -> (a -> m b) -> m b However, the definition of a Monad doesn’t guarantee the existence of a function of type Monad m => m a -&...

do-notation is syntactic sugar for monads. Here are the rules: do x <- mx do x <- mx y <- my is equivalent to do y <- my ... ... do let a = b let a = b in ...

The example below will collect the Device's OS version number and the the version of the application (which is defined in each projects' properties) that is entered into Version name on Android and Version on iOS. First make an interface in your PCL project: public interface INativeHelper { /...

Another useful feature is accessing your custom object collections as arrays in PHP. There are two interfaces available in PHP (>=5.0.0) core to support this: ArrayAccess and Iterator. The former allows you to access your custom objects as array. ArrayAccess Assume we have a user class and a da...

<?php $ch = curl_init(); //curl handler init curl_setopt($ch,CURLOPT_URL,"http://www.google.com/search?q=curl"); curl_setopt($ch,CURLOPT_RETURNTRANSFER,true);// set optional params curl_setopt($ch,CURLOPT_HEADER, false); $result=curl_exec($ch); ...

You can register for notifications of when the device text size is changed. Swift NSNotificationCenter.defaultCenter().addObserver(self, selector: #selector(updateFont), name: name:UIContentSizeCategoryDidChangeNotification, object: nil) Objective-C [[NSNotificationCenter defaultCenter] addObs...

$dbServer = "localhost,1234"; //Name of the server/instance, including optional port number (default is 1433) $dbName = "db001"; //Name of the database $dbUser = "user"; //Name of the user $dbPassword = "password"; //DB Password of that user $connectionI...

You have to create a different strings.xml file for every new language. Right-click on the res folder Choose New → Values resource file Select a locale from the available qualifiers Click on the Next button (>>) Select a language Name the file strings.xml strings.xml <resources&...

Intro An array is a container object that holds a number of values. In the following image you can see an array with size 10, the first element indexed 1 and the last element 10. Autohotkey offers a few ways of defining and creating arrays. Array := [] Array := Array() Creating and initia...

You can use the following code for going back and forward. if (!function_exists('codepoint_encode')) { function codepoint_encode($str) { return substr(json_encode($str), 1, -1); } } if (!function_exists('codepoint_decode')) { function codepoint_decode($str) { re...

Each resource directory under the res folder (listed in the example above) can have different variations of the contained resources in similarly named directory suffixed with different qualifier-values for each configuration-type. Example of variations of `` directory with different qualifier value...

Save the session variable as a variable. $session = Yii::$app->session; $sess = $session['keys']; Then create or update the array value you want $sess['first'] = 'abc'; And finally save to the session variable $session['keys'] = $sess

Returns true or false, which indicates whether the regexp is matched or not without updating $~ and other related variables. If the second parameter is present, it specifies the position in the string to begin the search. /R.../.match?("Ruby") #=> true /R.../.match?("Ruby&quot...

The static keyword is used on a class, method, or field to make them work independently of any instance of the class. Static fields are common to all instances of a class. They do not need an instance to access them. Static methods can be run without an instance of the class they are in. However...

Create a new project.json and example Program.cs: dotnet new Restore needed packages: dotnet restore Compile and run the example: dotnet run

ValueAnimator introduces a simple way to animate a value (of a particular type, e.g. int, float, etc.). The usual way of using it is: Create a ValueAnimator that will animate a value from min to max Add an UpdateListener in which you will use the calculated animated value (which you can obtain ...