Tutorial by Examples: en

Microbenchmark is useful for estimating the time taking for otherwise fast procedures. For example, consider estimating the time taken to print hello world. system.time(print("hello world")) # [1] "hello world" # user system elapsed # 0 0 0 This i...

As well as being able to create an array by filtering out nil from the transformed elements of a sequence, there is also a version of flatMap(_:) that expects the transformation closure to return a sequence S. extension SequenceType { public func flatMap<S : SequenceType>(transform: (Sel...

Having your scripts call Raycast directly may lead to problems if you need to change the collision matrices in the future, as you'll have to track down every LayerMask field to accommodate the changes. Depending on the size of your project, this may become a huge undertaking. Encapsulating Raycast ...

A branch is just a pointer to a commit, so you can freely move it around. To make it so that the branch is referring to the commit aabbcc, issue the command git reset --hard aabbcc Please note that this will overwrite your branch's current commit, and as so, its entire history. You might loose s...

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Using GNU grep grep -r 'pattern' <directory path> To also list line numbers of matches use -n option grep -rn 'pattern' <directory path> To search only files with particular glob pattern grep --include='*.txt' -r 'pattern' <directory path> Exclude file patterns or direc...

Variables declared inside a function only exist (unless passed) inside that function. x <- 1 foo <- function(x) { y <- 3 z <- x + y return(z) } y Error: object 'y' not found Variables passed into a function and then reassigned are overwritten, but only insi...

Variables can be assigned globally from any environment using <<-. bar() can now access y. bar <- function() { z <- x + y return(z) } foo <- function() { y <<- 3 z <- bar() return(z) } foo() 4 Global assignment is highly discourag...

Environments in R can be explicitly call and named. Variables can be explicitly assigned and call to or from those environments. A commonly created environment is one which encloses package:base or a subenvironment within package:base. e1 <- new.env(parent = baseenv()) e2 <- new.env(parent ...

Programming in general often requires a decision or a branch within the code to account for how the code operates under different inputs or conditions. Within the C# programming language (and most programming languages for this matter), the simplest and sometimes the most useful way of creating a br...

Following on from the If-Else Statement example, it is now time to introduce the Else If statement. The Else If statement follows directly after the If statement in the If-Else If-Else structure, but intrinsically has has a similar syntax as the If statement. It is used to add more branches to the c...

// Returns the nth number in the Fibonacci sequence function fibonacci(n) { if (n === 1 || n === 0) { return 1; } else { return fibonacci(n - 1) + fibonacci(n - 2); } }

Custom events usually need custom event arguments containing information about the event. For example MouseEventArgs which is used by mouse events like MouseDown or MouseUp events, contains information about Location or Buttons which used to generate the event. When creating new events, to create a...

A cancelable event can be raised by a class when it is about to perform an action that can be canceled, such as the FormClosing event of a Form. To create such event: Create a new event arg deriving from CancelEventArgs and add additional properties for event data. Create an event using EventH...

; We make single line comments by writing out text after a semicolon

#| We make block comments like this |#

In many instances, you will want to send data from the R server to the JS client. Here is a very simple example: library(shiny) runApp( list( ui = fluidPage( tags$script( "Shiny.addCustomMessageHandler('message', function(params) { alert(params); });" ), ...

REM This is a comment REM is the official comment command.

::This is a label that acts as a comment The double-colon :: comment shown above is not documented as being a comment command, but it is a special case of a label that acts as a comment. Caution: when labels are used as comments within a bracketed code block or for command, the command processor...

It is also possible to use variables as comments. This can be useful to conditionally prevent commands being executed: @echo off setlocal if /i "%~1"=="update" (set _skip=) Else (set _skip=REM) %_skip% copy update.dat %_skip% echo Update applied ... When using the ab...