Tutorial by Examples: u

Melting: The basics Melting is used to transform data from wide to long format. Starting with a wide data set: DT = data.table(ID = letters[1:3], Age = 20:22, OB_A = 1:3, OB_B = 4:6, OB_C = 7:9) We can melt our data using the melt function in data.table. This returns another data.table in long...

To use the library, you must include it as a dependency with the following line: compile project(':[library root directory]')

The PHP execution operator consists of backticks (``) and is used to run shell commands. The output of the command will be returned, and may, therefore, be stored in a variable. // List files $output = `ls`; echo "<pre>$output</pre>"; Note that the execute operator and sh...

PubNub Access Manager (PAM) extends PubNub's existing security framework by allowing developers to create and enforce secure access to channels throughout the PubNub Real Time Network. Access Manager allows you to manage granular permissions for your realtime apps and data streams, create multiple ...

fn copy_if<F>(slice: &[i32], pred: F) -> Vec<i32> where for<'a> F: Fn(&'a i32) -> bool { let mut result = vec![]; for &element in slice { if pred(&element) { result.push(element); } } result } This s...

Validate that an attribute's value matches a regular expression using format and the with option. class User < ApplicationRecord validates :name, format: { with: /\A\w{6,10}\z/ } end You can also define a constant and set its value to a regular expression and pass it to the with: option. ...

You can check if a value is included in an array using the inclusion: helper. The :in option and its alias, :within show the set of acceptable values. class Country < ApplicationRecord validates :continent, inclusion: { in: %w(Africa Antartica Asia Australia ...

If you use the [NonSerialized] attribute, then that member will always have its default value after deserialization (ex. 0 for an int, null for string, false for a bool, etc.), regardless of any initialization done in the object itself (constructors, declarations, etc.). To compensate, the attribut...

Implements a serialization surrogate selector that allows one object to perform serialization and deserialization of another As well allows to properly serialize or deserialize a class that is not itself serializable Implement ISerializationSurrogate interface public class ItemSurrogate : ISerial...

The first element of sys.argv[0] is the name of the python file being executed. The remaining elements are the script arguments. # script.py import sys print(sys.argv[0]) print(sys.argv) $ python script.py => script.py => ['script.py'] $ python script.py fizz => script.py ...

You can install NLTK over pip (pip install nltk).After it is installed, many components will not be present, and you will not be able to use some of NLTK's features. From your Python shell, run the function ntlk.download() to select which additional packages you want to install using UI. Alternati...

In order to sort a query, instead of using findAll(), you should use findAllSorted(). RealmResults<SomeObject> results = realm.where(SomeObject.class) .findAllSorted("sortField", Sort.ASCENDING); Note: sort() returns a completely new ...

Every synchronous query method (such as findAll() or findAllSorted()) has an asynchronous counterpart (findAllAsync() / findAllSortedAsync()). Asynchronous queries offload the evaluation of the RealmResults to another thread. In order to receive these results on the current thread, the current thre...

For queries, Realm provides the realmResults.asObservable() method. Observing results is only possible on looper threads (typically the UI thread). For this to work, your configuration must contain the following realmConfiguration = new RealmConfiguration.Builder(context) // ...

This example goes over how to set up CoreNLP from the latest official release. This example will take you through downloading the package, and running a simple command-line invocation of CoreNLP. Prerequisites: Java JVM 8. The command java -version should complete successfully with a line like: ...

In order to dynamically decide what beans to inject, we can use FactoryBeans. These are classes which implement the factory method pattern, providing instances of beans for the container. They are recognized by Spring and can be used transparently, without need to know that the bean comes from a fac...

Some languages have a native structure for sets. To make a set in Go, it's best practice to use a map from the value type of the set to an empty struct (map[Type]struct{}). For example, with strings: // To initialize a set of strings: greetings := map[string]struct{}{ "hi": {}, ...

Sometimes you want to have a file held in Git but ignore subsequent changes. Tell Git to ignore changes to a file or directory using update-index: git update-index --assume-unchanged my-file.txt The above command instructs Git to assume my-file.txt hasn't been changed, and not to check or repor...

If Go is not pre-installed in your system you can go to https://golang.org/dl/ and choose your platform to download and install Go. To set up a basic Go development environment, only a few of the many environment variables that affect the behavior of the go tool (See: Listing Go Environment Variabl...

A deadlock is what occurs when two or more threads are waiting for eachother to complete or to release a resource in such a way that they wait forever. If thread1 holds a lock on resource A and is waiting for resource B to be released while thread2 holds resource B and is waiting for resource A to ...