Tutorial by Examples: co

The command prompt comes pre-installed on all Windows NT, Windows CE, OS/2 and eComStation operating systems, and exists as cmd.exe, typically located in C:\Windows\system32\cmd.exe On Windows 7 the fastest ways to open the command prompt are: Press Win 𐌎, type "cmd" and then press ...

Single Pointers Pointer to an int The pointer can point to different integers and the int's can be changed through the pointer. This sample of code assigns b to point to int b then changes b's value to 100. int b; int* p; p = &b; /* OK */ *p = 100; /* OK */ Pointer to a cons...

Many commands and programs in the remote side are screen-based (e.g. mc) or they need to ask password (e.g. sudo), to be able to run these kind of programs you can use option -t. ssh -t [email protected] sudo ls / [sudo] password for alice: bin root dev etc home lib mnt opt proc root run usr ...

Managing AWS resources that scale up and down runs into the limits of the static inventory host file, that's why we need something dynamic. And that's what the dynamic inventories are for. Let's start: Download these ec2.ini and ec2.py files to the your project folder: cd my_ansible_project wget...

If you are using multiple namespaces that may have same-name classes(such as System.Random and UnityEngine.Random), you can use an alias to specify that Random comes from one or the other without having to use the entire namespace in the call. For instance: using UnityEngine; using System; Ran...

Built in functions can subset rows with columns that meet conditions. df <- data.frame(item = c(1:10), price_Elasticity = c(-0.57667, 0.03205, -0.04904, 0.10342, 0.04029, 0.0742, 0.1669, 0.0313, 0.22204, 0.06158), total...

CREATE TABLE stack( id INT, username VARCHAR(30) NOT NULL, password VARCHAR(30) NOT NULL ); INSERT INTO stack (`id`, `username`, `password`) VALUES (1, 'Foo', 'hiddenGem'); INSERT INTO stack (`id`, `username`, `password`) VALUES (2, 'Baa', 'verySecret'); Query SELECT id FROM ...

Query SELECT * FROM stack; Result +------+----------+----------+ | id | username | password | +------+----------+----------+ | 1 | admin | admin | | 2 | stack | stack | +------+----------+----------+ 2 rows in set (0.00 sec) You can select all columns from one table...

With the ~ selector, you can easily implement a global accessible boolean without using JavaScript. Add boolean as a checkbox To the very beginning of your document, add as much booleans as you want with a unique id and the hidden attribute set: <input type="checkbox" id="sideba...

Suppose you have complex code that creates and returns a list by starting with a blank list and repeatedly appending to it: def create(): result = [] # logic here... result.append(value) # possibly in several places # more logic... return result # possibly in several places...

First, Install gulp and gulp-concat plugin to your project localy npm install --save-dev gulp gulp-concat and add gulp-concat task to your gulpfile.js var gulp = require('gulp'); var concat = require('gulp-concat'); gulp.task('default', function() { }); gulp.task('css', function() { ...

An existing working copy can be quickly transformed to reflect the contents of a different branch in the same repository. For example, you might have a working copy of the trunk and now need to work on a development branch. Instead of checking out a completely new working copy (which can waste a l...

This topic is intended for intermediate to advanced F# developers "What are Monads?" is a common question. This is easy to answer but like in Hitchhikers guide to galaxy we realize we don't understand the answer because we didn't know what we were asking after. Many believe the way to un...

If you're doing multiple long calculations, you can run them at the same time on different threads on your computer. To do this, we make a new Thread and have it point to a different method. using System.Threading; class MainClass { static void Main() { var thread = new Thread(Seco...

Everything between /* and */ is commented. void main() { for (int i = 0; i < 5; i++) { /* This is commented, and will not affect code */ print('hello ${i + 1}'); } }

Given a file using ; as a column delimiter. Permuting the first and the second column is accomplished by awk -F';' -v 'OFS=;' '{ swap = $2; $2 = $1; $1 = swap; print }'

Given a file using ; as a column delimiter. We compute the mean of the values in the second column with the following program, the provided input is the list of grades of a student group: awk -F';' '{ sum += $2 } END { print(sum / NR) }' <<EOF Alice;2 Victor;1 Barbara;1 Casper;4 Deborah;...

We assume a file using ; as a column delimiter. Selecting a specific set of columns only requires a print statement. For instance, the following program selects the columns 3, 4 and 7 from its input: awk -F';' -v 'OFS=;' '{ print $3, $4, $7 }' It is as usual possible to more carefully choose lin...

Given a file using ; as a column delimiter. We compute the median of the values in the second column with the following program, written for GNU awk. The provided input is the list of grades of a student group: gawk -F';' '{ sample[NR] = $2 } END { asort(sample); if(NR % 2 == 1) { p...

For example we have WordCountService with countWords method: class WordCountService { def countWords(url: String): Map[String, Int] = { val sparkConf = new SparkConf().setMaster("spark://somehost:7077").setAppName("WordCount")) val sc = new SparkContext(sp...