Tutorial by Examples: du

By default, when data is imported to the PowerBI Desktop, each table or query stores data source details separately, even if they use the same data source. This makes it tedious, for example, to change the source database of an entire PowerBI report - which requires changing each query source param...

Convert from wide form to long form Load data USArrests from datasets. data("USArrests") head(USArrests) Murder Assault UrbanPop Rape Alabama 13.2 236 58 21.2 Alaska 10.0 263 48 44.5 Arizona 8.1 294 80 31.0 Arkansas 8...

Convert from long form to wide form To recover data from the previous example, use dcast like so. DTc <- dcast(DTmu, State + UrbanPop ~ Crime) This gives the data in the original wide form. State UrbanPop Murder Assault Rape 1: Alabama 58 13.2 236 21.2 2:...

When a new documentation tag is created, StackOverflow automatically generates an introductory topic, acting as a placeholder for the first actual topic. The introductory topic contains placeholder texts and pointers to point contributors in the right directions for helping expanding on the new doc...

Two of the most fundamental higher-order functions included in the standard library are map and filter. These functions are generic and can operate on any iterable. In particular, they are well-suited for computations on arrays. Suppose we have a dataset of schools. Each school teaches a particular...

Go to the Microsoft link for the OpenXML SDK download. Click the red download button. On the next screen click the box next to OpenXMLSDKToolV25.msi and click next to begin the download. Once the download is complete, launch the OpenXMLSDKToolV25.msi and follow the instructions on the screen. Th...

productFlavors { // Define separate dev and prod product flavors. dev { // dev utilizes minSDKVersion = 21 to allow the Android gradle plugin // to pre-dex each module and produce an APK that can be tested on // Android Lollipop without time c...

Why annotations? Generally we use annotation to facilitate the development and to make the code more clear and clean. What are annotations? Java 5 annotations provide standardization of metadata in a general goal. This metadata associated with Java features can be exploited in the compilation or ...

If you have an elixir file; a script or a module and want to load it into the current IEx session, you can use the c/1 method: iex(1)> c "lib/utils.ex" iex(2)> Utils.some_method This will compile and load the module in IEx, and you'll be able to call all of it's public methods. ...

It is a basic human instinct to assess risk and to accept or take some kind of action on that risk. This is the essence of security, which is the body of knowledge that provides a framework around this instinct. Security defines three key concepts in a triangular paradigm - Confidentiality, Integri...

Row-level security enables you to define some predicates that will control who could update rows in the table. First you need to define some table-value function that represents predicate that wll control access policy. CREATE FUNCTION dbo.pUserCanAccessProduct(@CompanyID int) RETURNS TABLE WIT...

#include <linux/init.h> #include <linux/module.h> /** * This function is called when the module is first loaded. */ static int __init hello_kernel_init(void) { printk("Hello, World!\n"); return 0; } /** * This function is called when is called if a...

In order to compile the driver, it is necessary to have the Linux Kernel source tree. Assuming the sources are at /lib/modules/<kernel-version>, the following Makefile will compile the file driver.c into the driver.ko Kernel Object obj-m := driver.o KDIR := /lib/modules/$(shell uname -r)/bu...

load($id); // or load it by SKU // $sku = "microsoftnatural"; // $_product = Mage::getModel('catalog/product')->loadByAttribute('sku', $sku); $stock = Mage::getModel('cataloginventory/stock_item')->loadByProduct($_product); print_r($stock->getData()); echo $stoc...

Spring is a vast framework, so the Spring framework has been divided in several modules which makes spring lightweight. Some important modules are: Spring Core Spring AOP Spring JDBC Spring Transaction Spring ORM Spring MVC All the modules of Spring are independent of each other except S...

Pygame has a module, pygame.draw, that contains functions which can draw shapes directly to a Surface. FunctionDescriptionpygame.draw.rectdraw a rectangle shapepygame.draw.polygondraw a shape with any number of sidespygame.draw.circledraw a circle around a pointpygame.draw.ellipsedraw a round shape...

You can always run JavaScript from inside itself, although this is strongly discouraged due to the security vulnerabilities it presents (see Remarks for details). To run JavaScript from inside JavaScript, simply use the below function: eval("var a = 'Hello, World!'");

Procedures, functions, triggers, and types written in .Net languages are stored in .dll files. Once you create .dll file containing CLR procedures you should import it into SQL Server: CREATE ASSEMBLY MyLibrary FROM 'C:\lib\MyStoredProcedures.dll' WITH PERMISSION_SET = EXTERNAL_ACCESS PERM...

If you have created .Net method in some class, compiled it into .dll, and imported it into SQL server as an assembly, you can create user-defined stored procedure that references method in that assembly: CREATE PROCEDURE dbo.DoSomethng(@input nvarchar(max)) AS EXTERNAL NAME MyLibrary.[Name.Space....

This is literally the only thing you need to start using RxJava on Android. Include RxJava and RxAndroid in your gradle dependencies: // use the last version compile 'io.reactivex.rxjava2:rxjava:2.1.1' compile 'io.reactivex.rxjava2:rxandroid:2.0.1' RxAndroid main addition to RxJava is a Sche...