Tutorial by Examples: r

UDP is a connectionless protocol. This means that peers sending messages do not require establishing a connection before sending messages. socket.recvfromthus returns a tuple (msg [the message the socket received], addr [the address of the sender]) A UDP server using solely the socket module: from...

The following will list up to ten of the most recently modified files in the current directory, using a long listing format (-l) and sorted by time (-t). ls -lt | head

From NSString: NSString *str = @"Hello world"; NSData *data = [str dataUsingEncoding:NSUTF8StringEncoding]; From Int: int i = 1; NSData *data = [NSData dataWithBytes: &i length: sizeof(i)]; You can also use the following methods: + dataWithContentsOfURL: + dataWithContentsO...

In this example we have an existing table, SuperHeros. This table contains a primary key ID. We will add a new table in order to store the powers of each super hero: CREATE TABLE HeroPowers ( ID int NOT NULL PRIMARY KEY, Name nvarchar(MAX) NOT NULL, HeroId int REFERENCES SuperHero...

NSDictionary *myDictionary = [[NSDictionary alloc] initWithObjectsAndKeys:@"value1", @"key1", @"value2", @"key2", nil]; NSArray *copiedArray = myDictionary.copy; Get keys: NSArray *keys = [myDictionary allKeys]; Get values: NSArray *values = [myDic...

NSDictionary *myDictionary = [[NSDictionary alloc] initWithObjectsAndKeys:@"value1", @"key1", @"value2", @"key2", nil]; NSData *myData = [NSKeyedArchiver archivedDataWithRootObject:myDictionary]; Reserve path: NSDictionary *myDictionary = (NSDictionary*...

NSDictionary *myDictionary = [[NSDictionary alloc] initWithObjectsAndKeys:@"value1", @"key1", @"value2", @"key2", nil]; NSMutableDictionary *mutableDictionary = [myDictionary mutableCopy]; NSData *data = [NSJSONSerialization dataWithJSONObject:myDiction...

Swift import SystemConfiguration /// Class helps to code reuse in handling internet network connections. class NetworkHelper { /** Verify if the device is connected to internet network. - returns: true if is connected to any internet network, false if is not co...

Although D3 is not specific for handling SVG elements, it is widely used for creating and manipulating complex SVG based data visualizations. D3 provides many powerful methods which helps to create various geometrical SVG structures with ease. It is recommended to understand basic concepts of SVG s...

\bfoo\b will match the complete word with no alphanumeric and _ preceding or following by it. Taking from regularexpression.info There are three different positions that qualify as word boundaries: Before the first character in the string, if the first character is a word character. After...

This guide assumes you already have Ruby installed. If you're using Ruby < 1.9 you'll have to manually install RubyGems as it won't be included natively. To install a ruby gem, enter the command: gem install [gemname] If you are working on a project with a list of gem dependencies, then the...

To generate true random values that can be used for cryptography std::random_device has to be used as generator. #include <iostream> #include <random> int main() { std::random_device crypto_random_generator; std::uniform_int_distribution<int> int_distribution(0,9); ...

A pseudo-random number generator generates values that can be guessed based on previously generated values. In other words: it is deterministic. Do not use a pseudo-random number generator in situations where a true random number is required. #include <iostream> #include <random> in...

The random number generator can (and should) be used for multiple distributions. #include <iostream> #include <random> int main() { std::default_random_engine pseudo_random_generator; std::uniform_int_distribution<int> int_distribution(0, 9); std::uniform_real_dis...

If you have a type definition file (d.ts) for the module, you can use an import statement. import _ = require('lodash'); If you don't have a definition file for the module, TypeScript will throw an error on compilation because it cannot find the module you are trying to import. In this case, yo...

//Swift let barButtonItem = UIBarButtonItem(title: "Greetings!", style: .Plain, target: self, action: #selector(barButtonTapped)) self.navigationItem.rightBarButtonItem = barButtonItem //Objective-C UIBarButtonItem *barButtonItem = [[UIBarButtonItem alloc] initWithTitle:@"Greeti...

Using code UILabel.lineBreakMode: NSLineBreakMode Swift label.lineBreakMode = .ByTruncatingTail .ByWordWrapping .ByCharWrapping .ByClipping .ByTruncatingHead .ByTruncatingTail .ByTruncatingMiddle Swift 3 label.lineBreakMode = .byTruncatingTail .byWordWrapping .byCharWrapping...

[a-b] where a and b are digits in the range 0 to 9 [3-7] will match a single digit in the range 3 to 7. Matching multiple digits \d\d will match 2 consecutive digits \d+ will match 1 or more consecutive digits \d* will match 0 or more consecutive digits \d{3} will ma...

By default, Interface Builder doesn't accept the CGColor datatype, so to allow adding a CGColor using user defined attributes in interface builder; one may want to use an extension like this: Swift Extension : extension CALayer { func borderUIColor() -> UIColor? { return borderCol...

Exceptions are errors which occur when a program is executing. Consider the Java program below which divides two integers. class Division { public static void main(String[] args) { int a, b, result; Scanner input = new Scanner(System.in); System.out.println(&qu...