Tutorial by Examples: e

Most performance tips are very dependent of the current state of JS engines and are expected to be only relevant at a given time. The fundamental law of performance optimization is that you must first measure before trying to optimize, and measure again after a presumed optimization. To measure cod...

The package's official wiki has some essential materials: As a new user, you will want to check out the vignettes, FAQ and cheat sheet. Before asking a question -- here on StackOverflow or anywhere else -- please read the support page. For help on individual functions, the syntax is h...

Go to application/model File name - Home_model.php Inside the file class Home_model extends CI_Model { public $variable; public function __construct() { parent::__construct(); } public function get_data() { $query = $this->db->get('tabl...

Syntax - $this->load->model('model_name'); Practice - $this->load->model('home_model'); If you would like your model assigned to a different object name you can specify it via the second parameter of the loading method: Syntax - $this->load->model('model_name', 'foobar'); ...

Syntax $this->load->model('model_name'); $this->model_name->method_name(); Practice $this->load->model('home_model'); $this->home_model->get_data();

Syntax $array = array( '' => , ); # can pass array $singelData = ''; # something just a filed value $this->load->model('model_name'); $this->model_name->method_name($singelData, $array); Practice $array = array( 'name' => 'codeigniter', 'version' =&g...

public function method_name($single, $array) { echo $single; print_r($array); } Beware with the order which pass from controller to model.

Javascript engines first look for variables within the local scope before extending their search to larger scopes. If the variable is an indexed value in an array, or an attribute in an associative array, it will first look for the parent array before it finds the contents. This has implications wh...

Open index.ios.js or index.android.js and delete everything between the <View> </View>. After that, write <Text> Hello World! </Text> and run the emulator. You should see Hello World! written on the screen! Congrats! You've successfully written your first Hello World!

ACID tables are supported since hive 0.14 version. Below table supports UPDATE/DELETE/INSERT Below configuration changes required in hive-site.xml. hive.support.concurrency = true hive.enforce.bucketing = true hive.exec.dynamic.partition.mode = nonstrict hive.txn.manager =org.apache.hadoop...

You can evaluate any valid C# code: int value = await CSharpScript.EvaluateAsync<int>("15 * 89 + 95"); var span = await CSharpScript.EvaluateAsync<TimeSpan>("new DateTime(2016,1,1) - DateTime.Now"); If type is not specified, the result is object: object value = ...

The CustomEvent API allows developers to create custom events and trigger them on DOM nodes, passing data along the way. event = new CustomEvent(typeArg, customEventInit); typeArg - DOMString representing the name of the event. customEventInit - is optional parameters (that will be passed as e ...

{-# LANGUAGE RecordWildCards #-} data Client = Client { firstName :: String , lastName :: String , clientID :: String } deriving (Show) printClientName :: Client -> IO () printClientName Client{..} = do p...

# example data DT = as.data.table(mtcars, keep.rownames = TRUE) Editing a column Use the := operator inside j to create new columns or modify existing ones: DT[, mpg_sq := mpg^2] Editing on a subset of rows Use the i argument to subset to rows "where" edits should be made: DT[1:...

To copy a data.frame as a data.table, use as.data.table or data.table: DF = data.frame(x = letters[1:5], y = 1:5, z = (1:5) > 3) DT <- as.data.table(DF) # or DT <- data.table(DF) This is rarely necessary. One exception is when using built-in datasets like mtcars, which must be copi...

It is generally not considered 'best practice' to re-purpose the reserved names of Properties or Methods as the name(s) of your own procedures and variables. Bad Form - While the following is (strictly speaking) legal, working code the re-purposing of the Find method as well as the Row, Column and ...

Basic syntax DT[where, select|update|do, by] syntax is used to work with columns of a data.table. The "where" part is the i argument The "select|update|do" part is the j argument These two arguments are usually passed by position instead of by name. A sequence of steps c...

# example data DT <- data.table(Titanic) Suppose that, for each sex, we want the rows with the highest survival numbers: DT[Survived == "Yes", .SD[ N == max(N) ], by=Sex] # Class Sex Age Survived N # 1: Crew Male Adult Yes 192 # 2: 1st Female Adult Yes...

# example data DT = data.table(iris) DT[, Bin := cut(Sepal.Length, c(4,6,8))] Suppose we want the summary function output for Sepal.Length along with the number of observations: DT[, c( as.list(summary(Sepal.Length)), N = .N ), by=.(Species, Bin)] # Species Bin Min. 1st Q...

To use just the time part of a Date use LocalTime. You can instantiate a LocalTime object in a couple ways LocalTime time = LocalTime.now(); time = LocalTime.MIDNIGHT; time = LocalTime.NOON; time = LocalTime.of(12, 12, 45); LocalTime also has a built in toString method that displays the for...