Tutorial by Examples: r

Teacher Class: class Teacher { private String name; private double salary; private String subject; public Teacher (String tname) { name = tname; } public String getName() { return name; } private double getSal...

Android now supports devices with 512MB of RAM. This documentation is intended to help OEMs optimize and configure Android 4.4 for low-memory devices. Several of these optimizations are generic enough that they can be applied to previous releases as well. Enable Low Ram Device flag We are introduc...

The CPU governor itself is just 1 C file, which is located in kernel_source/drivers/cpufreq/, for example: cpufreq_smartass2.c. You are responsible yourself for find the governor (look in an existing kernel repo for your device) But in order to successfully call and compile this file into your ke...

DispatchSemaphore provides an efficient implementation of a traditional counting semaphore, which can be used to control access to a resource across multiple execution contexts. A scenario for when to use a semaphore could be if you are doing some file reading/writing, if multiple tasks are t...

Swift 3 Serial Queue func serialQueues () { let serialQueue = DispatchQueue(label: "com.example.serial") //default queue type is a serial queue let start = Date () for i in 0...3 { //launch a bunch of tasks serialQueue.a...

This example echoes the special character ! into a file. This would only work when DelayedExpansion is disabled. When delayed expansion in enabled, you will need to use three carets and an exclamation mark like this: @echo off setlocal enabledelayedexpansion echo ^^^!>file echo ^>>&...

Redis provides the LPOP and RPOP commands as a counterpart to the LPUSH and RPUSH commands for fetching data items. If I was working with a list my_list that had several data items in it already, I can get the first item in the list using the LPOP command: LPOP my_list The result of this comman...

Redis supplies the SISMEMBER command to test if a particular item is already a member of a set. Using the SISMEMBER command I can test and see if apple is already a member of my fruit set. If I construct my fruit set from the previous example, I can check and see if it contains apple using the fol...

Redis provides the ZADD command to add items to a sorted set. The basic form of the ZADD command is to specify the set, the item to add and it's score. For example, if I wanted to construct an ordered set of my favorite food (from least to most), I could use either of: zadd favs 1 apple zadd fav...

You can enhance your kernel by adding new I/O schedulers if needed. Globally, governors and schedulers are the same; they both provide a way how the system should work. However, for the schedulers it is all about the input/output datastream except for the CPU settings. I/O schedulers decide how an u...

Redis provides seven different operations for working with scripts: Eval operations (EVAL, EVALSHA) SCRIPT operations (DEBUG, EXISTS, FLUSH, KILL, LOAD) The EVAL command evaluates a script provided as a string argument to the server. Scripts can access the specified Redis keys named as argum...

/** * Resizes an image using a Graphics2D object backed by a BufferedImage. * @param srcImg - source image to scale * @param w - desired width * @param h - desired height * @return - the new resized image */ private BufferedImage getScaledImage(Image srcImg, int w, int h){ //Cre...

The simpler way to use Bash in Windows is to install Git for Windows. It's shipped with Git Bash which is a real Bash. You can access it with shortcut in : Start > All Programs > Git > Git Bash Commands like grep, ls, find, sed, vi etc is working.

Be aware that the WebBrowser control is not sympathetic to your XAML definition, and renders itself over the top of other things. For example, if you put it inside a BusyIndicator that has been marked as being busy, it will still render itself over the top of that control. The solution is to bind th...

Insertion sort is one of the more basic algorithms in computer science. The insertion sort ranks elements by iterating through a collection and positions elements based on their value. The set is divided into sorted and unsorted halves and repeats until all elements are sorted. Insertion sort has c...

Bubble Sort This is a simple sorting algorithm that repeatedly steps through the list to be sorted, compares each pair of adjacent items and swaps them if they are in the wrong order. The pass through the list is repeated until no swaps are needed. Although the algorithm is simple, it is too slow ...

Selection sort is noted for its simplicity. It starts with the first element in the array, saving it's value as a minimum value (or maximum, depending on sorting order). It then itterates through the array, and replaces the min value with any other value lesser then min it finds on the way. That min...

Quicksort is one of the advanced algorithms. It features a time complexity of O(n log n) and applies a divide & conquer strategy. This combination results in advanced algorithmic performance. Quicksort first divides a large array into two smaller sub-arrays: the low elements and the high element...

g + geom_bar(aes(x = cut, fill = color), position = "fill") + guides(fill = guide_legend(title = NULL))

g + geom_bar(mapping = aes(x = cut, fill = clarity), position = "dodge") + theme(axis.text = element_text(colour = "red", size = 12))