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# example data DT1 = data.table(x = letters[1:2], y = 1:2, z = (1:2) > 3) Due to the way data.tables are manipulated, DT2 <- DT1 will not make a copy. That is, later modifications to the columns or other attributes of DT2 will affect DT1 as well. When you want a real copy, use DT2 = copy(...

# example data DT = data.table(Titanic) Suppose we only want to see second class: DT[ Class == "2nd" ] # Class Sex Age Survived N # 1: 2nd Male Child No 0 # 2: 2nd Female Child No 0 # 3: 2nd Male Adult No 154 # 4: 2nd Female Adult ...

# example data DT = data.table(Titanic) Suppose we want to see each class only if a majority survived: DT[, if (sum(N[Survived=="Yes"]) > sum(N[Survived=="No"]) ) .SD, by=Class] # Class Sex Age Survived N # 1: 1st Male Child No 0 # 2: 1st Fema...

Delete all nodes MATCH (n) DETACH DELETE n DETACH doesn't work in older versions(less then 2.3), for previous versions use MATCH (n) OPTIONAL MATCH (n)-[r]-() DELETE n, r Delete all nodes of a specific label MATCH (n:Book) DELETE n

Match (node_name:node_type {}), (node_name_two:node_type_two {}) CREATE (node_name)-[::edge_name{}]->(node_name_two)

The DISTINCT clause after SELECT eliminates duplicate rows from the result set. CREATE TABLE `car` ( `car_id` INT UNSIGNED NOT NULL PRIMARY KEY, `name` VARCHAR(20), `price` DECIMAL(8,2) ); INSERT INTO CAR (`car_id`, `name`, `price`) VALUES (1, 'Audi A1', '20000'); INSERT INTO CA...

A quick note before actually installing RabbitMQ: Ubuntu 14.04's Erlang packages have issues if you are using SSL with RabbitMQ, so you'll need to install a newer version than what the Ubuntu package maintainers provide, so use the binaries at https://www.erlang-solutions.com/resources/download.html...

Examples of monotonic predicates are: unification with (=)/2 or unify_with_occurs_check/2 dif/2, expressing disequality of terms CLP(FD) constraints like (#=)/2 and (#>)/2, using a monotonic execution mode. Prolog predicates that only use monotonic goals are themselves monotonic. Monoton...

Here are examples of how to use monotonic predicates instead of impure, non-monotonic constructs in your programs: dif/2 is meant to be used instead of non-monotonic constructs like (\=)/2 arithmetic constraints (CLP(FD), CLP(Q) and others) are meant to be used instead of moded arithmetic predi...

//Example 1 int[] array = { 1, 5, 2, 10, 7 }; // Select squares of all odd numbers in the array sorted in descending order IEnumerable<int> query = from x in array where x % 2 == 1 orderby x descending select x ...

To interact with WebElements in a webpage, first we need to identify the location of the element. By is the keyword available in selenium. You can locate the elements By.. By ID By Class Name By TagName By Name By Link Text By Partial Link Text By CSS Selector By XPath Using JavaScript ...

It is deemed best practice to always use Option Explicit in VBA as it forces the developer to declare all their variables before use. This has other benefits too, such as auto-capitalization for declared variable names and IntelliSense. Option Explicit Sub OptionExplicit() Dim a As Integer ...

List<Integer> nums = Arrays.asList(1, 2, 3); List<String> strings = nums.stream() .map(Object::toString) .collect(Collectors.toList()); That is: Create a stream from the list Map each element using Object::toString Collect the String values into a List using Collectors...

CSS div.needle { margin: 100px; height: 150px; width: 150px; transform: rotateY(85deg) rotateZ(45deg); /* presentational */ background-image: linear-gradient(to top left, #555 0%, #555 40%, #444 50%, #333 97%); box-shadow: inset 6px 6px 22px 8px #272727; } HTML <div c...

<svg height="80" width="160"> <ellipse cx="80" cy="40" rx="50" ry="30" style="fill:yellow; stroke:black; stroke-width:2" /> </svg> Rendered:

In general, UWP is used for making a single application that runs on Windows 10 across many different devices. However, it is also possible to make code tailored to specific devices. You can achieve this in several different ways. Different XAML Layout If you want to use a specific layout on for a...

The chan-signal crate provides a solution to handle OS signal using channels, altough this crate is experimental and should be used carefully. Example taken from BurntSushi/chan-signal. #[macro_use] extern crate chan; extern crate chan_signal; use chan_signal::Signal; fn main() { // S...

The nix crate provides an UNIX Rust API to handle signals, however it requires using unsafe rust so you should be careful. use nix::sys::signal; extern fn handle_sigint(_:i32) { // Be careful here... } fn main() { let sig_action = signal::SigAction::new(handle_sigint, ...

Unlike emails, JIDs were defined with Internationalization (i18n) in mind using the Preparation, Enforcement, and Comparison of Internationalized Strings (PRECIS) framework. PRECIS (defined in RFC 7564), is a framework for comparing strings safely in a variety of contexts. For instance, imagine you...

Adding a footer is not natively possible. Luckily, we can make use of jQuery and CSS to add a footer to the slides of an ioslides presentation rendered with knitr. First of all we have to include the jQuery plugin. This is done by the line <script src="https://ajax.googleapis.com/ajax/libs...