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Firebase synchronizes and stores a local copy of the data for active listeners when used on mobile devices. In addition, you can keep specific locations in sync. Android : DatabaseReference workoutsRef = FirebaseDatabase.getInstance().getReference("workouts"); scoresRef.keepSynced(true)...

Step 1: Download and extract Drupal Drupal is available in two supported versions: the most recent and the previous. Currently that is Drupal 8 (released November 2015) and Drupal 7. The Recommended releases are the latest stable releases of either version. To learn more about versions, see the Dru...

Index hints are used to force a query to use a specific index, instead of allowing SQL Server's Query Optimizer to choose what it deems the best index. In some cases you may gain benefits by specifying the index a query must use. Usually SQL Server's Query Optimizer chooses the best index suited for...

Now, let's imagine we have 1 large file (e.g. 30 GB) that needs to be converted, line by line. Say we have a script, convert.sh, that does this <task>. We can pipe contents of this file to stdin for parallel to take in and work with in chunks such as <stdin> | parallel --pipe --block &l...

var sourceFileName = "NonExistingFile"; try { System.IO.File.Copy(sourceFileName, "DestinationFile"); } catch (Exception e) { var stdErr = Console.Error; stdErr.WriteLine($"Failed to copy '{sourceFileName}': {e.Message}"); }

To get the list of Elixir modules just type h Elixir.[TAB] Pressing [TAB] autocompletes modules and functions names. In this case it lists all modules. To find all functions in a module e.g. List use h List.[TAB]

php -S localhost:80 PHP 7.1.7 Development Server started at Fri Jul 14 15:11:05 2017 Listening on http://localhost:80 Document root is C:\projetos\repgeral Press Ctrl-C to quit. This is the simplest way to start a PHP server that responds to request made to localhost at the port 80. The -S...

php -S localhost:80 -t project/public router.php PHP 7.1.7 Development Server started at Fri Jul 14 15:22:25 2017 Listening on http://localhost:80 Document root is /home/project/public Press Ctrl-C to quit.

This returns a map without the key-value pairs for the keys mentioned in the function argument. It can be used to remove information from existing map. (dissoc {:a 1 :b 2} :a) ;; {:b 2} It can also be used for dissocing multiple keys as: (dissoc {:a 1 :b 2 :c 3} :a :b) ;; {:c 3}

This is ANSI SQL method works in all the RDBMS. Widely used approach. CREATE TABLE AliasNameDemo (id INT,firstname VARCHAR(20),lastname VARCHAR(20)) INSERT INTO AliasNameDemo VALUES (1,'MyFirstName','MyLastName') SELECT FirstName +' '+ LastName As FullName FROM AliasNameDemo

This is my preferred approach. Nothing related to performance just a personal choice. It makes the code to look clean. You can see the resulting column names easily instead of scrolling the code if you have a big expression. CREATE TABLE AliasNameDemo (id INT,firstname VARCHAR(20),lastname VARCHAR(...

This is a weird approach most of the people don't know this even exist. CREATE TABLE AliasNameDemo(id INT,firstname VARCHAR(20),lastname VARCHAR(20)) INSERT INTO AliasNameDemo VALUES (1,'MyFirstName','MyLastName') SELECT * FROM (SELECT firstname + ' ' + lastname FROM A...

This syntax will be similar to using AS keyword. Just we don't have to use AS keyword CREATE TABLE AliasNameDemo (id INT,firstname VARCHAR(20),lastname VARCHAR(20)) INSERT INTO AliasNameDemo VALUES (1,'MyFirstName','MyLastName') SELECT FirstName +' '+ LastName FullName FROM AliasNa...

Tables are most easily included with the DT package, which is an R interface to the JavaScript library DataTables. library(shiny) library(DT) ui <- fluidPage( dataTableOutput('myTable') ) server <- function(input, output, session){ output$myTable <- renderDataTable({ dat...

Valgrind is GPLv2-licensed collection of dynamic analysis tools, which uses binary instrumentation (dynamic recompilation). Six tools are included to detect memory management (Memcheck) and threading errors (Helgrind and DRD), to generate call-graph and profile programs (with optional cache and bran...

One can use the command-line launching facility is when one wants to customize some aspects of the way MySQL Workbench operates. MySQL Workbench has the following common command line options: --admin instance - Launch MySQL Workbench and load the server instance specified. --query connection - ...

Arrays values should be accessed using a number specifying the location of the desired value in the array. This number is called Index. Indexes starts at 0 and finish at array length -1. To access a value, you have to do something like this: arrayName[index], replacing "index" by the num...

EPPlus also supports the ability to insert text in a cell using the Insert() method. For example: var file = new FileInfo(filePath); using (var p = new ExcelPackage(file)) { var wb = p.Workbook; var ws = wb.Worksheets.FirstOrDefault() ?? wb.Worksheets.Add("Sheet1"); var...

val re = """\((.*?)\)""".r val str = "(The)(example)(of)(repeating)(pattern)(in)(a)(single)(string)(I)(had)(some)(trouble)(with)(once)" re.findAllMatchIn(str).map(_.group(1)).toList res2: List[String] = List(The, example, of, repeating, pattern, in, a, ...

For this, we will use the function aggregate, which can be used as follows: aggregate(formula,function,data) The following code shows various ways of using the aggregate function. CODE: df = data.frame(group=c("Group 1","Group 1","Group 2","Group 2",&quo...