Tutorial by Examples: r

To prevent memory leaks, one should not forget to close an input stream or an output stream whose job is done. This is usually done with a try-catch-finally statement without the catch part: void writeNullBytesToAFile(int count, String filename) throws IOException { FileOutputStream out = null...

You can bind event listeners to the EventSource object to listen to different events channels using the .addEventListener method. EventSource.addEventListener(name: String, callback: Function, [options]) name: The name related to the name of the channel the server is emitting events to. callb...

Save aps.cer to a folder Open "Keychain access" and export the key that is under that certificate to a .p12 file (call it key.p12). To do that right click on it and choose Export. Save it to the same folder as step 1. On export you will be prompted for a password. Make something u...

Using redux directly with react might seem little difficult, As for every component you want to update when store changes, you have to subscribe that component to the redux store React Redux takes care of all these and makes it really easy to write components that can request the data it needs from...

What is Flink Like Apache Hadoop and Apache Spark, Apache Flink is a community-driven open source framework for distributed Big Data Analytics. Written in Java, Flink has APIs for Scala, Java and Python, allowing for Batch and Real-Time streaming analytics. Requirements a UNIX-like environment,...

JAXB can be used to generate classes from an model defined in XSD. It will then be possible to read XML document made against this XSD directly as java instances and inversly save these instances as XML document. Take the following XSD saved in a file named SimpleModel.xsd <?xml version="...

When an application has not been packaged as an executable JAR, you need to provide the name of an entry-point class on the java command line. Running the HelloWorld class The "HelloWorld" example is described in Creating a new Java program . It consists of a single class called HelloWo...

A Java entry-point class has a main method with the following signature and modifiers: public static void main(String[] args) Sidenote: because of how arrays work, it can also be (String args[]) When the java command starts the virtual machine, it loads the specified entry-point classes and...

The Factory method pattern is a creational pattern that abstracts away the instantiation logic of an object in order to decouple the client code from it. When a factory method belongs to a class that is an implementation of another factory pattern such as Abstract factory then it is usually more ap...

Detailed instructions on getting promise set up or installed.

Swift 2.3 let url = NSURL(string: "http://google.com/lastPath") let lastPath = url?.lastPathComponent Swift 3.0 let url = URL(string: "http://google.com/lastPath") let lastPath = url?.lastPathComponent

GET your REST data and store in a PowerShell object: $Post = Invoke-RestMethod -Uri "http://jsonplaceholder.typicode.com/posts/1" Modify your data: $Post.title = "New Title" PUT the REST data back $Json = $Post | ConvertTo-Json Invoke-RestMethod -Method Put -Uri "h...

GET your REST data and store in a PowerShell object: $Users = Invoke-RestMethod -Uri "http://jsonplaceholder.typicode.com/users" Modify many items in your data: $Users[0].name = "John Smith" $Users[0].email = "[email protected]" $Users[1].name = "Jane S...

Identify the item that is to be deleted and delete it: Invoke-RestMethod -Method Delete -Uri "http://jsonplaceholder.typicode.com/posts/1"

Date FormatSQL StatementSample OutputYY-MM-DDSELECT RIGHT(CONVERT(VARCHAR(10), SYSDATETIME(), 20), 8) AS [YY-MM-DD]SELECT REPLACE(CONVERT(VARCHAR(8), SYSDATETIME(), 11), '/', '-') AS [YY-MM-DD]11-06-08YYYY-MM-DDSELECT CONVERT(VARCHAR(10), SYSDATETIME(), 120) AS [YYYY-MM-DD]SELECT REPLACE(CONVERT(VAR...

These are the available editions of SQL Server, as told by the Editions Matrix: Express: Entry-level free database. Includes core-RDBMS functionality. Limited to 10G of disk size. Ideal for development and testing. Standard Edition: Standard Licensed edition. Includes core functionality and Busi...

SELECT Row_Number() OVER(ORDER BY UserName) As RowID, UserFirstName, UserLastName FROM Users From which it will yield a result set with a RowID field which you can use to page between. SELECT * FROM ( SELECT Row_Number() OVER(ORDER BY UserName) As RowID, UserFirstName, UserLastName ...

Julia's Char type represents a Unicode scalar value, which only in some cases corresponds to what humans perceive as a "character". For instance, one representation of the character é, as in résumé, is actually a combination of two Unicode scalar values: julia> collect("é&quot...

In Julia, you can have an Array that holds other Array type objects. Consider the following examples of initializing various types of Arrays: A = Array{Float64}(10,10) # A single Array, dimensions 10 by 10, of Float64 type objects B = Array{Array}(10,10,10) # A 10 by 10 by 10 Array. Each ele...

We can use the [] to create an empty Array in Julia. The simplest example would be: A = [] # 0-element Array{Any,1} Arrays of type Any will generally not perform as well as those with a specified type. Thus, for instance, we can use: B = Float64[] ## 0-element Array{Float64,1} C = Array{Flo...