Tutorial by Examples: le

dplyr introduces a grammar of data manipulation in R. It provides a consistent interface to work with data no matter where it is stored: data.frame, data.table, or a database. The key pieces of dplyr are written using Rcpp, which makes it very fast for working with in-memory data. dplyr's philosoph...

You can set or increase memory usage limits (or other JVM arguments) used for Gradle builds and the Gradle Daemon by editing $GRADLE_USER_HOME/.gradle/gradle.properties (~/.gradle/gradle.properties by default), and setting org.gradle.jvmargs. To configure these limits only for a specific project, e...

You can enable the Gradle Daemon to improve the performance of your builds. The Gradle Daemon keeps the Gradle Framework initialized and running, and caches project data in memory to improve performance. For a Single Build To enable the Daemon for a single build, you can simply pass the --daemon ...

Our first syntax example shows the animation shorthand property using all of the available properties/parameters: animation: 3s ease-in 1s 2 reverse both paused slidein; /* duration | timing-function | delay | iteration-count | di...

Dim surname As String 'surname can accept strings of variable length surname = "Smith" surname = "Johnson"

Guice is a Java library. To use it you have to add a JAR file into the classpath of your Java project. Sample classes Below are several classes for a "Hello, world!" example. An interface of a hello "service": public interface HelloWorldService { public void sayHello(); ...

This is an example of using Android Support Library V7 RecyclerView. Support libraries are generally recommended because they provide backward-compatible versions of new features, provide useful UI elements that are not included in the framework, and provide a range of utilities that apps can draw o...

The scope of a variable in a block { ... }, begins after declaration and ends at the end of the block. If there is nested block, the inner block can hide the scope of a variable which is declared in the outer block. { int x = 100; // ^ // Scope of `x` begins here // } // ...

To declare a single instance of a variable which is accessible in different source files, it is possible to make it in the global scope with keyword extern. This keyword says the compiler that somewhere in the code there is a definition for this variable, so it can be used everywhere and all write/r...

DECLARE @startdate CHAR(8), @numberDays TINYINT SET @startdate = '20160101' SET @numberDays = 10; WITH CTE_DatesTable AS ( SELECT CAST(@startdate as date) AS [date] UNION ALL SELECT DATEADD(dd, 1, [date]) FROM CTE_DatesTable WHERE DATEADD(dd, 1, [date]) <= DateAdd(DAY, @nu...

All variables in powershell begin with a US dollar sign ($). The simplest example of this is: $foo = "bar" This statement allocates a variable called foo with a string value of "bar".

To remove a variable from memory, one can use the Remove-Item cmdlet. Note: The variable name does NOT include the $. Remove-Item Variable:\foo Variable has a provider to allow most *-item cmdlets to work much like file systems. Another method to remove variable is to use Remove-Variable cmdlet...

Some recommended PEP8 style guidelines for imports: Imports should be on separate lines: from math import sqrt, ceil # Not recommended from math import sqrt # Recommended from math import ceil Order imports as follows at the top of the module: Standard libr...

You can install a gem from github or filesystem. If the gem has been checked out from git or somehow already on the file system, you could install it using gem install --local path_to_gem/filename.gem Installing gem from github. Download the sources from github mkdir newgem cd newgem git clon...

Comments are programmer-readable annotations that are ignored at runtime. Their purpose is to make source code easier to understand. Single line comments The # character is used to add single line comments. #!/usr/bin/ruby -w # This is a single line comment. puts "Hello World!" Whe...

'Declare an array of bytes, assign single-byte character codes, and convert to a string Dim singleByteChars(4) As Byte singleByteChars(0) = 72 singleByteChars(1) = 101 singleByteChars(2) = 108 singleByteChars(3) = 108 singleByteChars(4) = 111 Dim stringFromSingleByteChars As String stringFro...

As a root user: sudo nginx -s reload Ubuntu 14.04 example sudo service nginx reload Ubuntu 16.04 example sudo systemctl reload nginx Before reloading, it is a good idea to check config for syntax errors: sudo nginx -t Or sudo service nginx configtest

add filter method in RecyclerView.Adapter: public void filter(String text) { if(text.isEmpty()){ items.clear(); items.addAll(itemsCopy); } else{ ArrayList<PhoneBookItem> result = new ArrayList<>(); text = text.toLower...

We can easily separate distribution specific tasks and variables into different dedicated .yml files. Ansible helps us to automatically identify the target hosts distribution via {{ ansible_distribution }} and {{ ansible_distribution_version }}, so we just have to name the distribution dedicated .y...

We can provision remote systems with Ansible. You should have an SSH key-pair and you should take your SSH public key to the machine ~/.ssh/authorized_keys file. The porpuse is you can login without any authorization. Prerequisites: Ansible You need an Inventory file (for ex.: development.ini...