Tutorial by Examples: r

Enable the module by typing: sudo a2enmod ssl Restart the web server (apache2) so the change is recognized: sudo service apache2 restart Optional (but a good idea): Create a directory that will contain our new certificate files: sudo mkdir /etc/apache2/ssl Create the key and self-signed ...

Pointers can be dereferenced by adding an asterisk * before a pointer. package main import ( "fmt" ) type Person struct { Name string } func main() { c := new(Person) // returns pointer c.Name = "Catherine" fmt.Println(c.Name) // prints: Cathe...

A question that occasionally on StackOverflow is whether it is appropriate to use assert to validate arguments supplied to a method, or even inputs provided by the user. The simple answer is that it is not appropriate. Better alternatives include: Throwing an IllegalArgumentException using cust...

Sometimes it is needful to backtrack after reading. # identify current position in file, in case the first line isn't a comment my $current_pos = tell; while (my $line = readline $fh) { if ($line =~ /$START_OF_COMMENT_LINE/) { push @names, get_name_from_comment($line); ...

The WMI type provider allows you to query WMI services with strong typing. To output the results of a WMI query as JSON, open FSharp.Management open Newtonsoft.Json // `Local` is based off of the WMI available at localhost. type Local = WmiProvider<"localhost"> let data = ...

Classes implement an interface to meet the interface's contract. For example, a C# class may implement IDisposable, public class Resource : IDisposable { private MustBeDisposed internalResource; public Resource() { internalResource = new MustBeDisposed(); } ...

A Receiver Operating Characteristic (ROC) curve plots the TP-rate vs. the FP-rate as a threshold on the confidence of an instance being positive is varied Algorithm for creating an ROC curve sort test-set predictions according to confidence that each instance is positive step through ...

If you need to check if your testing method takes too long to execute, you can do that by mentioning your expected execution time using timeout property of @Test annotation. If the test execution takes longer than that number of milliseconds it causes a test method to fail. public class StringConca...

Function contracts allow the programer to check for inconsistencies. Inconsistencies include invalid parameters, checks for the correct return value or an invalid state of the object. The checks can happen before and after the body of the function or method is executed. void printNotGreaterThan42(...

For example if an method is invoked the state of the object may not allow that a method is called with specific parameters or not at all. class OlderThanEighteen { uint age; final void driveCar() in { assert(age >= 18); // variable must be in range } body { ...

Before running this sample, you must: Download and install the Java SE Development Kit (JDK): Download JDK Download Apache Maven version 3.3.9 or greater: Install and configure Maven for your local development environment.

We've created a simple Hello World app for Java so you can quickly get a feel for deploying an app to Google Cloud Platform. Follow these steps to download Hello World to your local machine. Clone the Hello World sample app repository to your local machine: git clone https://github.com/GoogleCloud...

To deploy your app to App Engine, you will need to register a project to create your project ID, which will determine the URL for the app. In the Cloud Platform Console, go to the Projects page and select or create a new project. Note the project ID you created above, and enter it in src/m...

Detailed instructions on getting sybase set up or installed.

Slices are pointers to arrays, with the length of the segment, and its capacity. They behave as pointers, and assigning their value to another slice, will assign the memory address. To copy a slice value to another, use the built-in copy function: func copy(dst, src []Type) int (returns the amount o...

With Option Strict On, although the .NET Framework allows the creation of single dimension arrays with non-zero lower bounds they are not "vectors" and so not compatible with VB.NET typed arrays. This means they can only be seen as Array and so cannot use normal array (index) references. ...

Since Qt 5.5 we have a new wonderful TreeView, a control we've all been waiting for. A TreeView implements a tree representation of items from a model. In general it looks like other QML views - ListView or TableView. But data structure of TreeView is more complex. A data in ListView or TableView...

import sympy as sy x1, x2 = sy.symbols("x1 x2") equations = [ sy.Eq( 2*x1 + 1*x2 , 10 ), sy.Eq( 1*x1 - 2*x2 , 11 ) ] print sy.solve(equations) # Result: {x1: 31/5, x2: -12/5}

sort command is used to sort a list of lines. Input from a file sort file.txt Input from a command You can sort any output command. In the example a list of file following a pattern. find * -name pattern | sort

import sympy as sy x, y = sy.symbols("x y") # nsolve needs the (in this case: two) equations, the names of the variables # (x,y) we try to evaluate solutions for, and an initial guess (1,1) for the # solution print sy.nsolve((x**3+sy.exp(y)-4,x+3*y),(x,y),(1,1)) The result s...