In Ruby, there is always an implicit receiver for all method calls. The language keeps a reference to the current implicit receiver stored in the variable self. Certain language keywords like class and module will change what self points to. Understanding these behaviors is very helpful in mastering...
When you define a class or module, the implicit receiver becomes a reference to the class itself. For example:
puts "I am #{self}"
class Example
puts "I am #{self}"
end
Executing the above code will print:
"I am main"
"I am Example"
BEGIN TRY -- start error handling
BEGIN TRANSACTION; -- from here on transactions (modifictions) are not final
-- start your statement(s)
select 42/0 as ANSWER -- simple SQL Query with an error
-- end your statement(s)
COMMIT TRANSACTION; -- finalize all transa...
The first thing we need is to tell karma to use Webpack to read our tests, under a configuration we set for the webpack engine. Here, I am using babel because I write my code in ES6, you can change that for other flavors, such as Typescript. Or I use Pug (formerly Jade) templates, you don't have to....
Before reading and writing text files you should know what encoding to use. See the Perl Unicode Documentation for more details on encoding. Here we show the setting of UTF-8 as the default encoding and decoding for the function open. This is done by using the open pragma near the top of your code (...
SELECT 1,22,44
UNION
SELECT 2,33,55
SELECT 1,22,44
UNION
SELECT 2,33,55
UNION
SELECT 2,33,55
The result is the same as above.
use UNION ALL
when
SELECT 1,22,44
UNION
SELECT 2,33,55
UNION ALL
SELECT 2,33,55
Method 1:
proc sql;
create table foo like sashelp.class;
quit;
Method 2:
proc sql;
create table bar as
select * from sashelp.class (obs=0);
quit;
Method 1 should be the preferred option
The Maven Surefire plugin runs during the test phase of the Maven build process or when test is specified as a Maven goal. The following directory structure and minimum pom.xml file will configure Maven to run a test.
Directory structure inside the project's root directory:
─ project_root
├─ p...
Most of linux distros stores its version info in the /etc/lsb-release (debian) or /etc/redhat-release (RPM based) file. Using below generic command should get you past most of the Debian and RPM derivatives as Linux Mint and Cent-Os.
Example on Ubuntu Machine:
cat /etc/*release
DISTRIB_ID=Ubuntu
...
The sample content used here is Tears of Steel, by Blender Foundation. Specifically, we will use the download titled "HD 720p (~365MB, mov, 2.0)". This is a single file that ends with the extension "mov" and will play in just about any modern media player.
Note that the download...
This example will explore how to see the layout of a video track and how to extract the individual pictures within it.
The sample content used here is Tears of Steel, by Blender Foundation. Specifically, we will use the download titled "HD 720p (~365MB, mov, 2.0)". This is a single file t...
DASH is the most widely deployed adaptive streaming technology in modern solutions, used to deliver video in a wide variety of scenarios. The best way to understand DASH presentations is to observe the network activity that takes place during playback.
This example uses Fiddler to capture and analy...
Mongoose connect has 3 parameters, uri, options, and the callback function. To use them see sample below.
var mongoose = require('mongoose');
var uri = 'mongodb://localhost:27017/DBNAME';
var options = {
user: 'user1',
pass: 'pass'
}
mongoose.connect(uri, options, function(err){...
By default, all the controllers you generate with Symfony's built-in generate:controller command will make use of Symfony annotations for routing:
namespace AppBundle\Controller;
// You have to add a use statement for the annotation
use Sensio\Bundle\FrameworkExtraBundle\Configuration\Route;
...
JSON is a very strict format (see http://json.org). That makes it easy to parse and write for machines but surprises humans when an inconspicuous mistakes breaks the document.
Common Problems
Trailing Comma
Unlike most programming languages your are not allowed to add a trailing comma:
{
a: 1...
Log on to the Azure classic portal.
In the left navigation pane of the portal, click Service Bus.
In the lower pane of the portal, click Create.
In the Add a new namespace dialog, enter a namespace name. The system immediately checks to see if the name is available.
After...
@IBAction func axisChange(sender: UISwitch) {
UIView.animateWithDuration(1.0) {
self.updateConstraintsForAxis()
}
}
The updateConstraintForAxis function just sets the axis of the stack view containing the two image views:
private func updateConstraintsForAxis() {
if (axi...
The simple use-case is to refer to a single icon in its normal size:
<i class="fa fa-camera-retro"></i> (View result in this fiddle.)
Create an empty tag (it is recommended to use <i> used for that) and assign class "fa" and the class corresponding to the desi...
A shader program, in the OpenGL sense, contains a number of different shaders. Any shader program must have at least a vertex shader, that calculates the position of the points on the screen, and a fragment shader, that calculates the colour of each pixel. (Actually the story is longer and more co...
Recursive use of make means using make as a command within a makefile. This technique is useful when a large project contains sub-directories, each having their respective makefiles. The following example will help understand advantage of using .PHONY with recursive make.
/main
|_ Makefile
...
