Tutorial by Examples: t

Whereas Classes are more like blueprints, Objects are static (i.e. already instantiated): object Dog { def bark: String = "Raf" } Dog.bark() // yields "Raf" They are often used as a companion to a class, they allow you to write: class Dog(val name: String) { } ...

Lubridate provides ymd() series of functions for parsing character strings into dates. The letters y, m, and d correspond to the year, month, and day elements of a date-time. mdy("07-21-2016") # Returns Date ## [1] "2016-07-21" mdy("07-21-2016", t...

date <- now() date ## "2016-07-22 03:42:35 IST" year(date) ## 2016 minute(date) ## 42 wday(date, label = T, abbr = T) # [1] Fri # Levels: Sun < Mon < Tues < Wed < Thurs < Fri < Sat day(date) <- 31 ## "2016-07-31 03:42:35 IST" # If an ...

An instant is a specific moment in time. Any date-time object that refers to a moment of time is recognized as an instant. To test if an object is an instant, use is.instant. library(lubridate) today_start <- dmy_hms("22.07.2016 12:00:00", tz = "IST") # default tz="UT...

Intervals are simplest way of recording timespans in lubridate. An interval is a span of time that occurs between two specific instants. # create interval by substracting two instants today_start <- ymd_hms("2016-07-22 12-00-00", tz="IST") today_start ## [1] "2016-07-...

now_dt <- ymd_hms(now(), tz="IST") now_dt ## [1] "2016-07-22 13:53:09 IST" round_date() takes a date-time object and rounds it to the nearest integer value of the specified time unit. round_date(now_dt, "minute") ## [1] "2016-07-22 13:53:00 IST" r...

Unlike durations, periods can be used to accurately model clock times without knowing when events such as leap seconds, leap days, and DST changes occur. start_2012 <- ymd_hms("2012-01-01 12:00:00") ## [1] "2012-01-01 12:00:00 UTC" # period() considers leap year calculati...

with_tz returns a date-time as it would appear in a different time zone. nyc_time <- now("America/New_York") nyc_time ## [1] "2016-07-22 05:49:08 EDT" # corresponding Europe/Moscow time with_tz(nyc_time, tzone = "Europe/Moscow") ## [1] "2016-07-22 12:49:...

Using Homebrew Prerequisites: Make sure you're on OS X 10.9 (Mavericks) or above, and have Homebrew installed. Run the following in your terminal: brew update && brew install rethinkdb Compile from source Building RethinkDB from source requires OS X 10.9 (Mavericks) or greater. Xcode...

GROUP BY is used in combination with aggregation functions. Consider the following table: orderIduserIdstoreNameorderValueorderDate143Store A2520-03-2016257Store B5022-03-2016343Store A3025-03-2016482Store C1026-03-2016521Store A4529-03-2016 The query below uses GROUP BY to perform aggregated calc...

When something fails in your transaction code and you want to undo it, you can rollback your transaction: BEGIN TRY BEGIN TRANSACTION INSERT INTO Users(ID, Name, Age) VALUES(1, 'Bob', 24) DELETE FROM Users WHERE Name = 'Todd' COMMIT TRANSACTION END TRY...

kotlin-gradle-plugin is used to compile Kotlin code with Gradle. Basically, its version should correspond to the Kotlin version you want to use. E.g. if you want to use Kotlin 1.0.3, then you need to aplly kotlin-gradle-plugin version 1.0.3 too. It's a good idea to externalize this version in gradl...

Protocol Oriented Programming is a useful tool in order to easily write better unit tests for our code. Let's say we want to test a UIViewController that relies on a ViewModel class. The needed steps on the production code are: Define a protocol that exposes the public interface of the class Vi...

You can use fprintf on a file just like you might on a console with printf. For example to keep track of game wins, losses and ties you might write /* saves wins, losses and, ties */ void savewlt(FILE *fout, int wins, int losses, int ties) { fprintf(fout, "Wins: %d\nTies: %d\nLosses: %d...

The POSIX C library defines the getline() function. This function allocates a buffer to hold the line contents and returns the new line, the number of characters in the line, and the size of the buffer. Example program that gets each line from example.txt: #include <stdlib.h> #include <s...

import ( "io/ioutil" "path/filepath" "gopkg.in/yaml.v2" ) func main() { filename, _ := filepath.Abs("config/config.yml") yamlFile, err := ioutil.ReadFile(filename) var config Config err = yaml.Unmarshal(yamlFile, &c...

Creating a hub A quick configuration for a hub and node setup in selenium grid. For more information see: Grid 2 docs Requirements To set up a grid hub you need the flowing: Selenium-server-standalone-.jar Creating the hub To Create a Hub you need to run the selenium server. Download Se...

Extension methods are useful for adding functionality to enumerations. One common use is to implement a conversion method. public enum YesNo { Yes, No, } public static class EnumExtentions { public static bool ToBool(this YesNo yn) { return yn == YesNo.Yes; ...

Using a custom inspector allows you to change the way a script is drawn in the Inspector. Sometimes you want to add extra information in the inspector for your script that isn't possible to do with a custom property drawer. Below is a simple example of a custom object that with using a custom inspe...

Sometimes you have custom objects that contain data but do not derive from MonoBehaviour. Adding these objects as a field in a class that is MonoBehaviour will have no visual effect unless you write your own custom property drawer for the object's type. Below is a simple example of a custom object,...