Tutorial by Examples: r

Sometimes it's necessary to be able to extract values from an object using only references (ie. without transferring ownership). struct Token { pub id: u32 } struct User { pub token: Option<Token> } fn main() { // Create a user with an arbitrary token let user = User...

Let's say we have the following data: >>> data = {"cats": [{"name": "Tubbs", "color": "white"}, {"name": "Pepper", "color": "black"}]} Just dumping this as JSON does not do anything special here: ...

Have a table NameAgeCityBob10ParisMat20BerlinMary24Prague select Name from table where Age>10 AND City='Prague' Gives NameMary select Name from table where Age=10 OR City='Prague' Gives NameBobMary

A vector is denoted by square brackets: [] ;;=> [] [:foo] ;;=> [:foo] [:foo :bar] ;;=> [:foo :bar] [1 (+ 1 1) 3] ;;=> [1 2 3] In addition using to the literal syntax, you can also use the vector function to construct a vector: (vector) ;;=> [] (vector :foo) ;;=&...

For if you have to fine-tune what is published. import { Mongo } from 'meteor/mongo'; import { Meteor } from 'meteor/meteor'; import { Random } from 'meteor/random'; if (Meteor.isClient) { // established this collection on the client only. // a name is required (first parameter) and this...

On the server, you can create a publication like this. this.userId is the id of the user who is currently logged in. If no user is logged in, you might want to throw an error and respond to it. import Secrets from '/imports/collections/Secrets'; Meteor.publish('protected_data', function () { ...

Swift 3 let stackView = UIStackView() stackView.axis = .horizontal stackView.alignment = .fill // .leading .firstBaseline .center .trailing .lastBaseline stackView.distribution = .fill // .fillEqually .fillProportionally .equalSpacing .equalCentering let label = UILabel() label.text = "...

Swift let stackView = UIStackView() stackView.axis = .Vertical stackView.alignment = .Fill // .Leading .FirstBaseline .Center .Trailing .LastBaseline stackView.distribution = .Fill // .FillEqually .FillProportionally .EqualSpacing .EqualCentering let label = UILabel(frame: CGRectZero) label....

Using the dateutil library as in the previous example on parsing timezone-aware timestamps, it is also possible to parse timestamps with a specified "short" time zone name. For dates formatted with short time zone names or abbreviations, which are generally ambiguous (e.g. CST, which coul...

By default all datetime objects are naive. To make them timezone-aware, you must attach a tzinfo object, which provides the UTC offset and timezone abbreviation as a function of date and time. Fixed Offset Time Zones For time zones that are a fixed offset from UTC, in Python 3.2+, the datetime mod...

It is often helpful to have MATLAB print the 1st line of a function, as this usually contains the function signature, including inputs and outputs: dbtype <functionName> 1 Example: >> dbtype fit 1 1 function [fitobj,goodness,output,warnstr,errstr,convmsg] = fit(xdatain,ydatain,f...

The boolean type cannot be cast to/from any other primitive type. A char can be cast to/from any numeric type by using the code-point mappings specified by Unicode. A char is represented in memory as an unsigned 16-bit integer value (2 bytes), so casting to byte (1 byte) will drop 8 of those bits (...

Numeric primitives can be cast in two ways. Implicit casting happens when the source type has smaller range than the target type. //Implicit casting byte byteVar = 42; short shortVar = byteVar; int intVar = shortVar; long longVar = intvar; float floatVar = longVar; double doubleVar = floatVar...

Note: you need to install Boot before trying this example out. See the Installation and Setup section if you haven't installed it yet. Boot allows making executable Clojure files using shebang (#!) line. Place the following text into a file of your choice (this example assumes it's in the "cur...

The simplest use case is using the subprocess.call function. It accepts a list as the first argument. The first item in the list should be the external application you want to call. The other items in the list are arguments that will be passed to that application. subprocess.call([r'C:\path\to\a...

In Angular $scope is the glue between the Controller and the View that helps with all of our data binding needs. Controller As is another way of binding controller and view and is mostly recommended to use. Basically these are the two controller constructs in Angular (i.e $scope and Controller As). ...

It is possible to extract a date out of a text using the dateutil parser in a "fuzzy" mode, where components of the string not recognized as being part of a date are ignored. from dateutil.parser import parse dt = parse("Today is January 1, 2047 at 8:21:00AM", fuzzy=True) pr...

A tbl_df (pronounced tibble diff) is a variation of a data frame that is often used in tidyverse packages. It is implemented in the tibble package. Use the as_data_frame function to turn a data frame into a tbl_df: library(tibble) mtcars_tbl <- as_data_frame(mtcars) One of the most notable ...

Although it is possible to create a fragment constructor with parameters, Android internally calls the zero-argument constructor when recreating fragments (for example, if they are being restored after being killed for Android's own reasons). For this reason, it is not advisable to rely on a constru...

let string1 = "Hello" //simple string let string2 = "Line\nNewLine" //string with newline escape sequence let string3 = @"Line\nSameLine" //use @ to create a verbatim string literal let string4 = @"Line""with""quoutes inside" //dou...