Tutorial by Examples: r

The partition of an integer is a way of writing it as a sum of positive integers. For example, the partitions of the number 5 are: 5 4 + 1 3 + 2 2 + 2 + 1 2 + 1 + 1 + 1 1 + 1 + 1 + 1 + 1 Notice that changing the order of the summands will not create a different partition. The partition f...

public class IntegerPartition { public static int[,] Result = new int[100,100]; private static int Partition(int targetNumber, int largestNumber) { for (int i = 1; i <= targetNumber; i++) { for (int j = 1; j <= largestNumber; j++) ...

Sometimes we need cross domain request for our API's in laravel. We need to add appropriate headers to complete the cross domain request successfully. So we need to make sure that whatever headers we are adding should be accurate otherwise our API's become vulnerable. In order to add headers we nee...

<?php namespace laravel\Http\Middleware; class CorsHeaders { /** * This must be executed _before_ the controller action since _after_ middleware isn't executed when exceptions are thrown and caught by global handlers. * * @param $request * @param \Closure $next * @pa...

This is an example of using until/retries/delay to implement an alive check for a webapp that is starting up. It assumes that there will be some period of time (up to 3 minutes) where the webapp is refusing socket connections. After that, it checks the /alive page for the word "OK". It als...

For small functions that get called often, the overhead associated with the function call can be a significant fraction of the total execution time of that function. One way of improving performance, then, is to eliminate the overhead. In this example we use four functions (plus main()) in three so...

Go to the [https://developers.facebook.com/](https://developers.facebook.com/) and create your app. Click Add product and choose Facebook Login

If you enable prettyUrl in your yii2-app, your redirect_uri will be: http://<base_url>/web/site/auth And disable pretty url: http://<base_url>/web/index.php?r=site%2Fauth Example:

/** * @param $client ClientInterface */ public function onAuthSuccess($client) { //Get user info /** @var array $attributes */ $attributes = $client->getUserAttributes(); $email = ArrayHelper::getValue($attributes, 'email'); //email info $id = ArrayHelper::getValue(...

Persistence is created in docker containers using volumes. Let's create a Limesurvey container and persist the database, uploaded content and configuration in a named volume: docker volume create --name mysql docker volume create --name upload docker run -d --name limesurvey -v mysql:/var/lib/m...

This document explains how to get Google Access tokens and use them to get Google Analytics data to be displayed in our websites. Example: A live example is available in https://newtonjoshua.com note: Use the same gmail account for all the below steps. STEP 1: Set Up Google Analytics Foll...

Parameters of these operators are lhs and rhs operator== tests if both elements on lhs and rhs pair are equal. The return value is true if both lhs.first == rhs.first AND lhs.second == rhs.second, otherwise false std::pair<int, int> p1 = std::make_pair(1, 2); std::pair<int, int> ...

When calling driver.Navigate().GoToUrl(url);, the code execution stops until the page is fully loaded. This is sometimes unnecessary when you just want to extract data. Note: The code samples below could be considered hacks. There is no "official" way of doing this. Create a new thread...

# Define which servers to include in the load balancing scheme. # It's best to use the servers' private IPs for better performance and security. upstream backend { ip_hash; server 10.10.10.10 slow_start=30s max_fails=3 fail_timeout=15s; server 10.10.10.12 slow_start=30s max_fa...

XPATH <Animal> <legs>4</legs> <eyes>2</eyes> <horns>2</horns> <tail>1</tail> </Animal> XPATH boolean(/Animal/horns) OUTPUT true

XML <House> <LivingRoom> <plant name="rose"/> </LivingRoom> <TerraceGarden> <plant name="passion fruit"/> <plant name="lily"/> <plant name="golden duranta"/> ...

SELECT CURRENT_DATE + '1 day'::INTERVAL SELECT '1999-12-11'::TIMESTAMP + '19 days'::INTERVAL SELECT '1 month'::INTERVAL + '1 month 3 days'::INTERVAL

SELECT string_agg(<TABLE_NAME>.<COLUMN_NAME>, ',') FROM <SCHEMA_NAME>.<TABLE_NAME> T

DELETE FROM <SCHEMA_NAME>.<Table_NAME> WHERE ctid NOT IN ( SELECT MAX(ctid) FROM <SCHEMA_NAME>.<TABLE_NAME> GROUP BY <SCHEMA_NAME>.<TABLE_NAME>.* ) ;

select * from dict