Tutorial by Examples: r

Fortran 2003 introduced support for object oriented programming. This feature allows to take advantage of modern programming techniques. Derived types are defined with the following form: TYPE [[, attr-list] :: ] name [(name-list)] [def-stmts] [PRIVATE statement or SEQUENCE statement]. . . ...

In order to obtain class-like behavior, type and related procedures (subroutine and functions) shall be placed in a module: Example: module MShape implicit none private type, public :: Shape private integer :: radius contains procedure :: set => sh...

C++11 std::string supports iterators, and so you can use a ranged based loop to iterate through each character: std::string str = "Hello World!"; for (auto c : str) std::cout << c; You can use a "traditional" for loop to loop through every character: std::stri...

var request = new XMLHttpRequest(); request.onreadystatechange = (e) => { if (request.readyState !== 4) { return; } if (request.status === 200) { console.log('success', request.responseText); } else { console.warn('error'); } }; request.open('GET', 'https://my...

Note: You cannot develop react-native apps for iOS on Windows, only react-native android apps. The official setup docs for react-native on windows can be found here. If you need more details there is a granular guide here. Tools/Environment Windows 10 command line tool (eg Powershell or window...

Starting with Asp.net 4.5 web controls can take advantage from strongly-typed binding to get IntelliSense support and compiletime errors. Create a class, which holds your model: public class Album { public int Id { get; set; } public string Name { get; set; } public string Artist {...

Let's say we have model Travel with many related fields: class Travel(models.Model): tags = models.ManyToManyField( Tag, related_name='travels', ) route_places = models.ManyToManyField( RoutePlace, related_name='travels', ) coordinate = models.F...

Converting an NSDate object to string is just 3 steps. 1. Create an NSDateFormatter object Swift let dateFormatter = NSDateFormatter() Swift 3 let dateFormatter = DateFormatter() Objective-C NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init]; 2. Set the date format in whic...

You can use Gradle to auto-increment your package version each time you build it. To do so create a version.properties file in the same directory as your build.gradle with the following contents: VERSION_MAJOR=0 VERSION_MINOR=1 VERSION_BUILD=1 (Changing the values for major and minor as you s...

class Skill(models.Model): name = models.CharField(max_length=50) description = models.TextField() class Developer(models.Model): name = models.CharField(max_length=50) skills = models.ManyToManyField(Skill, through='DeveloperSkill') class DeveloperSkill(models.Model): ...

int squareNum (int a) { return a*a; } int : return type squareNum : function name int a : parameter type and name return a*a : return a value (same type as the return type defined at the beginning)

int val = 0; // variable used to store the value // coming from the sensor void setup() { Serial.begin(9600); //Begin serializer to print out value // Note: Analogue pins are // automatically set as inputs } void loop() { val = analogRead(0); // read the va...

This simple example provides an explanation on some functions I found extremely useful since I have started using MATLAB: cellfun, arrayfun. The idea is to take an array or cell class variable, loop through all its elements and apply a dedicated function on each element. An applied function can eith...

The use of Matlab Coder sometimes denies the use of some very common functions, if they are not compatible to C++. Relatively often there exist undocumented helper functions, which can be used as replacements. Here is a comprehensive list of supported functions.. And following a collection of alte...

In MATLAB versions prior to R2014b, using the old HG1 graphics engine, it was not obvious how to create color coded 2D line plots. With the release of the new HG2 graphics engine arose a new undocumented feature introduced by Yair Altman: n = 100; x = linspace(-10,10,n); y = x.^2; p = plot(x,y,'r...

Since Matlab R2014b it is easily possible to achieve semi-transparent markers for line and scatter plots using undocumented features introduced by Yair Altman. The basic idea is to get the hidden handle of the markers and apply a value < 1 for the last value in the EdgeColorData to achieve the d...

While it's often tempting to catch every Exception: try: very_difficult_function() except Exception: # log / try to reconnect / exit gratiously finally: print "The END" # it runs no matter what execute. Or even everything (that includes BaseException and all its c...

Sometimes it is useful to create union types with only one case to implement record-like types: type Point = Point of float * float let point1 = Point(0.0, 3.0) let point2 = Point(-2.5, -4.0) These become very useful because they can be decomposed via pattern matching in the same way as tu...

Let's say we have a class MyClass with no constructor argument: class MyClass In Scala we can instantiate it using below syntax: val obj = new MyClass() Or we can simply write: val obj = new MyClass But, if not paid attention, in some cases optional parenthesis may produce some unexpecte...

Array.prototype.map(): Returns a new array with the results of calling a provided function on every element in the original array. The following code example takes an array of persons and creates a new array containing persons with a 'fullName' property var personsArray = [ { id: 1, f...