Tutorial by Examples: r

A source code file is a (generally) plain text file which is to processed by the compiler. A source code file may contain up to one main program and any number of modules and external subprograms. For example, a source code file may contain the following module mod1 end module mod1 module mod...

As a root user run: nginx -s reopen

/*(8)*/ SELECT /*9*/ DISTINCT /*11*/ TOP /*(1)*/ FROM /*(3)*/ JOIN /*(2)*/ ON /*(4)*/ WHERE /*(5)*/ GROUP BY /*(6)*/ WITH {CUBE | ROLLUP} /*(7)*/ HAVING /*(10)*/ ORDER BY /*(11)*/ LIMIT The order in which a query is processed and description of each section. V...

Elasticsearch is accessed through a HTTP REST API, typically using the cURL library. The messages between the search server and the client (your or your application) are sent in the form of JSON strings. By default, Elasticsearch runs on port 9200. In the examples below, ?pretty is added to tell El...

Partial classes provide an ability to split class declaration (usually into separate files). A common problem that can be solved with partial classes is allowing users to modify auto-generated code without fearing that their changes will be overwritten if the code is regenerated. Also multiple devel...

01. Underline Text :- Single/Double Line , Strike Through :- Single/Double Line Step 1 Select the Label and change the label type Plain to Attributed Step 2 Click the label text and Right click Step 3 Then click Font -> Show Fonts Step 4 Then font view will show up and click under...

// Get the current colors of the gradient. let oldColors = self.gradientLayer.colors // Define the new colors for the gradient. let newColors = [UIColor.red.cgColor, UIColor.yellow.cgColor] // Set the new colors of the gradient. self.gradientLayer.colors = newColors // Initia...

Driver: 12c R1 11g R2 (Note: the driver is not included in Maven Central!) Driver class initialization: Class.forName("oracle.jdbc.driver.OracleDriver"); Connection URL Older format, with SID "jdbc:oracle:thin:@<hostname>:<port>:<SID>" Newer...

Padding Remember, members of a struct are usually padded to ensure they are aligned on their natural boundary: struct t { int a, b, c, d; // a is at offset 0, b at 4, c at 8, d at 0ch char e; // e is at 10h short f; // f is at 12h (naturally aligned) lo...

array_reduce reduces array into a single value. Basically, The array_reduce will go through every item with the result from last iteration and produce new value to the next iteration. Usage: array_reduce ($array, function($carry, $item){...}, $defaul_value_of_first_carry) $carry is the result f...

Python will implicitly convert any object to a Boolean value for testing, so use it wherever possible. # Good examples, using implicit truth testing if attr: # do something if not attr: # do something # Bad examples, using specific types if attr == 1: # do something if att...

The query attribute on queryset gives you SQL equivalent syntax for your query. >>> queryset = MyModel.objects.all() >>> print(queryset.query) SELECT "myapp_mymodel"."id", ... FROM "myapp_mymodel" Warning: This output should only be used for d...

To get First object: MyModel.objects.first() To get last objects: MyModel.objects.last() Using Filter First object: MyModel.objects.filter(name='simple').first() Using Filter Last object: MyModel.objects.filter(name='simple').last()

A typeglob *foo holds references to the contents of global variables with that name: $foo, @foo, $foo, &foo, etc. You can access it like an hash and assign to manipulate the symbol tables directly (evil!). use v5.10; # necessary for say our $foo = "foo"; our $bar; say ref *foo{SCAL...

open(my $fh, '<', "/some/path") or die $!; my @ary = <$fh>; When evaluated in list context, the diamond operator returns a list consisting of all the lines in the file (in this case, assigning the result to an array supplies list context). The line terminator is retained, and ...

XE2 program CrossPlatformHelloWorld; uses FMX.Dialogs; {$R *.res} begin ShowMessage('Hello world!'); end. Most of the Delphi supported platforms (Win32/Win64/OSX32/Android32/iOS32/iOS64) also support a console so the WriteLn example fits them well. For the platforms that require...

When Intel designed the original x86, the 8086 (and 8088 derivative), they included Segmentation to allow the 16-bit processor to access more than 16 bits worth of address. They did this by making the 16-bit addresses be relative to a given 16-bit Segment Register, of which they defined four: Code S...

Introduction When the 80286 was invented, it supported the legacy 8086 Segmentation (now called "Real Mode"), and added a new mode called "Protected Mode". This mode has been in every x86 processor since, albeit enhanced with various improvements such as 32- and 64-bit addressin...

Switching into Protected Mode is easy: you just need to set a single bit in a Control Register. But staying in Protected Mode, without the CPU throwing up its hands and resetting itself due to not knowing what to do next, takes a lot of preparation. In short, the steps required are as follows: ...

The easiest way to write Processing code is to simply call a series of functions. Press the run button in the Processing editor, and Processing will run your code. Here's an example: size(200, 200); background(0, 0, 255); fill(0, 255, 0); ellipse(100, 100, 100, 100); This code creates a 200x2...