Tutorial by Examples: r

For any object (i.e, variable, array, union, struct, pointer or function) the unary address operator can be used to access the address of that object. Suppose that int i = 1; int *p = NULL; So then a statement p = &i;, copies the address of the variable i to the pointer p. I...

Please see here: Pointer Arithmetic

An immutable object is an object whose state cannot be changed. An immutable class is a class whose instances are immutable by design, and implementation. The Java class which is most commonly presented as an example of immutability is java.lang.String. The following is a stereotypical example: ...

You can pass parameters to I18n t method: # Example config/locales/en.yml en: page: users: "%{users_count} users currently online" # In models, controller, etc... I18n.t('page.users', users_count: 12) # In views # ERB <%= t('page.users', users_count: 12) %> #S...

You can let I18n handle pluralization for you, just use count argument. You need to set up your locale file like this: # config/locales/en.yml en: online_users: one: "1 user is online" other: "%{count} users are online" And then use the key you just created by ...

In most cases, you may want to set I18n locale. One might want to set the locale for the current session, the current user, or based on a URL parameter This is easily achievable by implementing a before_action in one of your controllers, or in ApplicationController to have it in all of your controll...

Array.join(separator) can be used to output an array as a string, with a configurable separator. Default (separator = ","): ["a", "b", "c"].join() === "a,b,c" With a string separator: [1, 2, 3, 4].join(" + ") === "1 + 2 + 3 + 4&q...

<?xml version="1.0" encoding="utf-8" ?> <Employees> <Employee> <EmpId>1</EmpId> <Name>Sam</Name> <Sex>Male</Sex> <Phone Type="Home">423-555-0124</Phone> <Phone Type="Work&quot...

# this method can be anything and anywhere as long as it is accessible for connection @pyqtSlot() def run_on_complete(): pass # An object containing methods you want to run in a thread class Worker(QObject): complete = pyqtSignal() @pyqtSlot() def a_method_to_run...

Like JavaScript, numbers are floating point values. let pi: number = 3.14; // base 10 decimal by default let hexadecimal: number = 0xFF; // 255 in decimal ECMAScript 2015 allows binary and octal. let binary: number = 0b10; // 2 in decimal let octal: number = 0o755; // 493 in de...

Textual data type: let singleQuotes: string = 'single'; let doubleQuotes: string = "double"; let templateString: string = `I am ${ singleQuotes }`; // I am single

An array of values: let threePigs: number[] = [1, 2, 3]; let genericStringArray: Array<string> = ['first', '2nd', '3rd'];

Number formatting, grouping digits according to the localization. const usNumberFormat = new Intl.NumberFormat('en-US'); const esNumberFormat = new Intl.NumberFormat('es-ES'); const usNumber = usNumberFormat.format(99999999.99); // "99,999,999.99" const esNumber = esNumberFormat.form...

Currency formatting, grouping digits and placing the currency symbol according to the localization. const usCurrencyFormat = new Intl.NumberFormat('en-US', {style: 'currency', currency: 'USD'}) const esCurrencyFormat = new Intl.NumberFormat('es-ES', {style: 'currency', currency: 'EUR'}) const u...

Date time formatting, according to the localization. const usDateTimeFormatting = new Intl.DateTimeFormat('en-US'); const esDateTimeFormatting = new Intl.DateTimeFormat('es-ES'); const usDate = usDateTimeFormatting.format(new Date('2016-07-21')); // "7/21/2016" const esDate = esDateT...

Add one common horizontal line for all categorical variables # sample data df <- data.frame(x=('A', 'B'), y = c(3, 4)) p1 <- ggplot(df, aes(x=x, y=y)) + geom_bar(position = "dodge", stat = 'identity') + theme_bw() p1 + geom_hline(aes(yintercept=5), colour=...

To convert decimal number to binary format use base 2 Int32 Number = 15; Console.WriteLine(Convert.ToString(Number, 2)); //OUTPUT : 1111 To convert decimal number to octal format use base 8 int Number = 15; Console.WriteLine(Convert.ToString(Number, 8)); //OUTPUT : 17 To conv...

The most feasible way is to use, the DateTime class. An example: <?php // Create a date time object, which has the value of ~ two years ago $twoYearsAgo = new DateTime("2014-01-18 20:05:56"); // Create a date time object, which has the value of ~ now $now = new DateTime("2016...

Specially useful for has_and_belongs_to_many relation, you can manually create a join table using the create_table method. Suppose you have two models Tags and Proyects, and you'd like to associate them using a has_and_belongs_to_many relation. You need a join table to associate instances of both c...

A GridLayout is a layout manager which places components inside a grid with equal cell sizes. You can set the number of rows, columns, the horizontal gap and the vertical gap using the following methods: setRows(int rows) setColumns(int columns) setHgap(int hgap) setVgap(int vgap) or you ca...