Tutorial by Examples: r

An atomic type can be used to safely read and write to a memory location shared between two threads. A Bad example that is likely to cause a data race: #include <thread> #include <iostream> //function will add all values including and between 'a' and 'b' to 'result' void add(int...

docker run --name="test-app" --entrypoint="/bin/bash" example-app This command will override the ENTRYPOINT directive of the example-app image when the container test-app is created. The CMD directive of the image will remain unchanged unless otherwise specified: docker run -...

docker run --add-host="app-backend:10.15.1.24" awesome-app This command adds an entry to the container's /etc/hosts file, which follows the format --add-host <name>:<address>. In this example, the name app-backend will resolve to 10.15.1.24. This is particularly useful for t...

A good way to learn about Elm is to try writing some expressions in the REPL (Read-Eval-Print Loop). Open a console in your elm-app folder (that you have created in the Initialize and build phase) and try the following: $ elm repl ---- elm-repl 0.17.1 ----------------------------------------------...

For this example, we will use the vector: > x <- 11:20 > x [1] 11 12 13 14 15 16 17 18 19 20 R vectors are 1-indexed, so for example x[1] will return 11. We can also extract a sub-vector of x by passing a vector of indices to the bracket operator: > x[c(2,4,6)] [1] 12 14 16 ...

0.170.18.0 At the time of writing (July 2016) elm-reactor has been temporarily stripped of its time traveling functionality. It's possible to get it, though, using the jinjor/elm-time-travel package. It's usage mirrors Html.App or Navigation modules' program* functions, for example instead of: im...

> List.repeat 3 "abc" ["abc","abc","abc"] : List String You can give List.repeat any value: > List.repeat 2 {a = 1, b = (2,True)} [{a = 1, b = (2,True)}, {a = 1, b = (2,True)}] : List {a : Int, b : (Int, Bool)}

By default, List.sort sorts in ascending order. > List.sort [3,1,5] [1,3,5] : List number List.sort needs the list elements to be comparable. That means: String, Char, number (Int and Float), List of comparable or tuple of comparable. > List.sort [(5,"ddd"),(4,"zzz"),...

List.sortWith allows you to sort lists with data of any shape - you supply it with a comparison function. compareBools : Bool -> Bool -> Order compareBools a b = case (a,b) of (False, True) -> LT (True, False) -> GT _ -> ...

Note: this is not very efficient due to the nature of List (see Remarks below). It will be better to construct the list the "right" way from the beginning than to construct it and then reverse it. > List.reverse [1,3,5,7,9] [9,7,5,3,1] : List number

By default List.sort sorts in ascending order, with the compare function. There are two ways to sort in descending order: one efficient and one inefficient. The efficient way: List.sortWith and a descending comparison function. descending a b = case compare a b of LT -> GT ...

List.sortBy allows to use a function on the elements and use its result for the comparison. > List.sortBy String.length ["longest","short","medium"] ["short","medium","longest"] : List String -- because the lengths are: [7,5,6] It ...

/** * @param num Numerator * @param denom Denominator * @throws ArithmeticException in case `denom` is `0` */ class Division @throws[ArithmeticException](/*no annotation parameters*/) protected (num: Int, denom: Int) { private[this] val wrongValue = num / denom /** Integer n...

This simple macro annotation outputs the annotated item as-is. import scala.annotation.{compileTimeOnly, StaticAnnotation} import scala.reflect.macros.whitebox.Context @compileTimeOnly("enable macro paradise to expand macro annotations") class noop extends StaticAnnotation { def m...

C++14 Those following duration user literals are declared in the namespace std::literals::chrono_literals, where both literals and chrono_literals are inline namespaces. Access to these operators can be gained with using namespace std::literals, using namespace std::chrono_literals, and using names...

Open the Visual Basic Editor ( see Opening the Visual Basic Editor ) Click Insert --> Module to add a new Module : Copy and Paste the following code in the new module : Sub hello() MsgBox "Hello World !" End Sub To obtain : Click on the green “play” arr...

Open Excel Open the Visual Basic Editor ( see Opening the Visual Basic Editor ) Add a new module by clicking Insert --> Module : Copy and Paste the following code in the new module : Public Function Hello() As String 'Note: the output of the function is simply the function's name ...

We can get facts (ansible_os_family, ansible_pkg_mgr) with Ad-Hoc command of setup module and filter. ansible_os_family: $ ansible all -m setup -a 'filter=ansible_os_family' ra.local | SUCCESS => { "ansible_facts": { "ansible_os_family": "Debi...

Paramorphisms model primitive recursion. At each iteration of the fold, the folding function receives the subtree for further processing. para :: Functor f => (f (Fix f, a) -> a) -> Fix f -> a para f = f . fmap (\x -> (x, para f x)) . unFix The Prelude's tails can be modelled as ...

Apomorphisms model primitive corecursion. At each iteration of the unfold, the unfolding function may return either a new seed or a whole subtree. apo :: Functor f => (a -> f (Either (Fix f) a)) -> a -> Fix f apo f = Fix . fmap (either id (apo f)) . f Note that apo and para are dual...