Tutorial by Examples: re

An equation of the type f(x)=0 is either algebraic or transcendental. These types of equations can be solved by using two types of methods- Direct Method: This method gives the exact value of all the roots directly in a finite number of steps. Indirect or Iterative Method: Iterative method...

The navigation pane located at the left hand side of the admin panel is how you navigate to and access different administration functionalities in the OpenCart back end. Pane expander Current account name and role Dashboard Catalog Categories Products Recurring Profiles Filters Attrib...

To connect to a server we must use SSH on the client as follows, # ssh -p port user@server-address port - The listening ssh port of the server (default port 22). user - Must be an existing user on the server with SSH privileges. server address - The IP/Domain of the server. For a real wor...

C++11 Similarly to this cv-qualifiers, we can also apply ref-qualifiers to *this. Ref-qualifiers are used to choose between normal and rvalue reference semantics, allowing the compiler to use either copy or move semantics depending on which are more appropriate, and are applied to *this instead of...

First off, let's assume this is your initial model, inside an application called discography: from django.db import models class Album(models.Model): name = models.CharField(max_length=255) artist = models.CharField(max_length=255) Now, you realize that you want to use a ForeignKey ...

Akka Streams allows you to easily create a stream leveraging the power of the Akka framework without explicitly defining actor behaviors and messages. Every stream will have at least one Source (origin of the data) and at least one Sink (destination of the data). import akka.actor.ActorSystem impo...

By utilizing the pre_save we can determine if a save action on our database was about updating an existing object or creating a new one. In order to achieve this you can check the state of the model object: @receiver(pre_save, sender=User) def pre_save_user(sender, instance, **kwargs): ...

Installing Vua Redux from NPM: Install through: npm i vua-redux --save Initialize: =============== // main.js import Vue from 'vue'; import { reduxStorePlugin } from 'vua-redux'; import AppStore from './AppStore'; import App from './Component/App'; // install vua-redux Vue.use(redux...

We have a DataListComponent that shows a data we pull from a service. DataListComponent also has a PagerComponent as it's child. PagerComponent creates page number list based on total number of pages it gets from the DataListComponent. PagerComponent also lets the DataListComponent know when user c...

The members of a union share the same space in memory. This means that writing to one member overwrites the data in all other members and that reading from one member results in the same data as reading from all other members. However, because union members can have differing types and sizes, the da...

Here I have shared a code snippet for implementing endless scrolling in recycle view. Step 1: First make a one abstract method in Recycleview adapter like below. public abstract class ViewAllCategoryAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> { public abstract void lo...

DECLARE @ID AS INT; SET @ID = (SELECT MIN(ID) from TABLE); WHILE @ID IS NOT NULL BEGIN PRINT @ID; SET @ID = (SELECT MIN(ID) FROM TABLE WHERE ID > @ID); END

RwLocks allow a single producer provide any number of readers with data while preventing readers from seeing invalid or inconsistent data. The following example uses RwLock to show how a single producer thread can periodically increase a value while two consumers threads are reading the value. use...

Viewchild offers one way interaction from parent to child. There is no feedback or output from child when ViewChild is used. We have a DataListComponent that shows some information. DataListComponent has PagerComponent as it's child. When user makes a search on DataListComponent, it gets a data fro...

Suppose, that we have three users : The Administrator of the database > admin The application with a full access for her data > read_write The read only access > read_only With below queries, you can set access privileges on objects created in the future in specified schema. ALTER ...

Schema changes: You will need to define a new field type in your solr schema file and then you can create fields of that type. Example schema snippet: <!-- Source: solr/example/.../conf/schema.xml --> <?xml version="1.0" encoding="UTF-8" ?> <schema name="a...

Let's get some theoretical knowledge before moving to the example. There are three important terms being used here Analyzers, Tokenizers, and Filters. To create such custom field you will need to create an analyzer with one tokenizer and one or more filters. As mentioned here, you can have only one ...

You can parse XML from a string or from a XML file 1. From a string $xml_obj = simplexml_load_string($string); 2. From a file $xml_obj = simplexml_load_file('books.xml'); Example of parsing Considering the following XML: <?xml version="1.0" encoding="UTF-8"?> &l...

Objective-C Create a new iOS project and add CoreSpotlight and MobileCoreServices framework to your project. Create the actual CSSearchableItem and associating the uniqueIdentifier, domainIdentifier and the attributeSet. Finally index the CSSearchableItem using [[CSSearchableIndex defaul...

Aggregation is used to perform complex data search operations in the mongo query which can't be done in normal "find" query. Create some dummy data: db.employees.insert({"name":"Adma","dept":"Admin","languages":["german","f...