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A bi-directional value converter utilizes two methods in your Value Converter class: toView and fromView these methods are aptly named to signify which direction the data is flowing. In our example we will be creating a prepend Value Converter which will make sure that an amount entered in our app ...

A Value Converter can be used alongside other value converters and you can infinitely chain them using the | pipe separator. ${myString | toUppercase | removeCharacters:'&,%,-,+' | limitTo:25} The above theoretical example firstly applies toUppercase which capitalizes our string. Then it app...

Similar to hsl() notation, but with an added alpha (opacity) value. hsla(240, 100%, 50%, 0) /* transparent */ hsla(240, 100%, 50%, 0.5) /* half-translucent blue */ hsla(240, 100%, 50%, 1) /* fully opaque blue */ Syntax hsla(<hue>, <saturation>%, <lightness>%, <a...

Stateless components are getting their philosophy from functional programming. Which implies that: A function returns all time the same thing exactly on what is given to it. For example: const statelessSum = (a, b) => a + b; let a = 0; const statefulSum = () => a++; As you can see fro...

Recursion occurs when a function call causes that same function to be called again before the original function call terminates. For example, consider the well-known mathematical expression x! (i.e. the factorial operation). The factorial operation is defined for all nonnegative integers as follows:...

updateState by key can be used to create a stateful DStream based on upcoming data. It requires a function: object UpdateStateFunctions { def updateState(current: Seq[Double], previous: Option[StatCounter]) = { previous.map(s => s.merge(current)).orElse(Some(StatCounter(current))) } ...

mapWithState, similarly to updateState, can be used to create a stateful DStream based on upcoming data. It requires StateSpec: import org.apache.spark.streaming._ object StatefulStats { val state = StateSpec.function( (key: String, current: Option[Double], state: State[StatCounter]) =&g...

/** * @param year Full year as int (ex: 2000). * @param month Month as int, zero-based (ex: 0=January, 11=December). */ function daysInMonth(year:int, month:int):int { return (new Date(year, ++month, 0)).date; }

The simplest case is just preforming a task for a fixed known number of times. Say we want to display the numbers between 1 to n, we can write: n = 5; for k = 1:n display(k) end The loop will execute the inner statement(s), everything between the for and the end, for n times (5 in this ex...

yii migrate/create <name> The required name argument gives a brief description about the new migration. For example, if the migration is about creating a new table named news, you may use the name create_news_table and run the following command yii migrate/create create_news_table

<?php use yii\db\Migration; class m150101_185401_create_news_table extends Migration { public function up() { } public function down() { echo "m101129_185401_create_news_table cannot be reverted.\n"; return false; } /* // Use safeUp/safeDown to run migra...

yii migrate/down # revert the most recently applied migration yii migrate/down 3 # revert the most 3 recently applied migrations

public function safeUp() { $this->createTable('news', [ 'id' => $this->primaryKey(), 'title' => $this->string()->notNull(), 'content' => $this->text(), ]); $this->insert('news', [ 'title' => 'test 1', 'conte...

yii migrate/redo # redo the last applied migration yii migrate/redo 3 # redo the last 3 applied migrations

yii migrate/history # showing the last 10 applied migrations yii migrate/history 5 # showing the last 5 applied migrations yii migrate/history all # showing all applied migrations yii migrate/new # showing the first 10 new migrations yii migrate/new 5 # showing the first 5 ...

yii migrate/mark 150101_185401 # using timestamp to specify the migration yii migrate/mark "2015-01-01 18:54:01" # using a string that can be parsed by strtotime() yii migrate/mark m150101_185401_create_news_table # using full name yii migrate/mark 13...

yii migrate This command will list all migrations that have not been applied so far. If you confirm that you want to apply these migrations, it will run the up() or safeUp() method in every new migration class, one after another, in the order of their timestamp values. If any of the migrations fa...

Set memory limit and disable swap limit docker run -it -m 300M --memory-swap -1 ubuntu:14.04 /bin/bash Set both memory and swap limit. In this case, container can use 300M memory and 700M swap. docker run -it -m 300M --memory-swap 1G ubuntu:14.04 /bin/bash

We can use Predefined Constants for Date format in date() instead of the conventional date format strings since PHP 5.1.0. Predefined Date Format Constants Available DATE_ATOM - Atom (2016-07-22T14:50:01+00:00) DATE_COOKIE - HTTP Cookies (Friday, 22-Jul-16 14:50:01 UTC) DATE_RSS - RSS (Fri, 22...

Installation Requirements The minimum requirement by this project template is that your Web server supports PHP 5.4.0. Yii2-advanced-app can be installed in two ways. They are Installing via Composer Installing from an Archive File 1) Installing via Composer If you do not already have Comp...