rtCamp notes, day 6/undefined

PHP

What’s new in PHP 7

Speed Improvement – PHP 7 is a lot more faster than the previous versions of PHP
Scalar Type Declaration – any calls made to the functions specified must strictly adhere to the specified types
Return Type Declarations – Adding a return type ensures that only an expected value type returns.

Benefits:

The new implementation of Type Declaration certainly help in making the code easier to read. With PHP 7 you get a versatile type declaration methods which makes your life easier. You can even see at the start of the function, what is required and what will be returned.

Commonly used string functions

strlen() – Return the Length of a String
str_word_count() – Count Words in a String
strrev() – Reverse a String
strpos() – Search For a Text Within a String
str_replace() – Replace Text Within a String

strpos() can also be used to check if a string contains a substring by the following code

$a = 'How are you?';

if (strpos($a, 'are') !== false) {
    echo 'true';
}

PHP DATE

Characteristics for date:

d – Represents the day of the month (01 to 31)
m – Represents a month (01 to 12)
Y – Represents a year (in four digits)
l (lowercase ‘L’) – Represents the day of the week

Usage: date(characterstic) : date('Y-m-d');

Require or Include?

require will produce a fatal error (E_COMPILE_ERROR) and stop the script
include will only produce a warning (E_WARNING) and the script will continue

PHP SESSION

Sessions are used to save user data throughout the pages, by creating a session via cookie

Start a session with session_start();
Retrieve or set session data via $_SESSION['xyz']; or $_SESSION['xyz'] = 'value';
Clear a session by session_unset();
Delete session session_destroy();, deletes cookies as well

Validating data = Determine if the data is in proper form.

Sanitizing data = Remove any illegal character from the data.

Object-Oriented Programming

OOP is faster and easier to execute
OOP provides a clear structure for the programs
Helps create reusable code

PHP Constructor

A constructor is automatically called when you initiate a class.

function __construct()

PHP Destructor

A desctructor is automatically called when the end of the code is reached.

function __destruct()

PHP – Access Modifiers

public – the property or method can be accessed from everywhere. This is default
protected – the property or method can be accessed within the class and by classes derived from that class
private – the property or method can ONLY be accessed within the class

PHP – Inheritance

When a class derives from another class. The child class will inherit all the public and protected properties and methods from the parent class.

PHP – Class Constants

Constants cannot be changed once it is declared. Class constants can be useful if you need to define some constant data within a class. A class constant is declared inside a class with the const keyword.

PHP – Abstract Classes and Methods

Abstract classes and methods are when the parent class has a named method, but need its child class(es) to fill out the tasks.

<?php
abstract class ParentClass {
  abstract public function someMethod1();
  abstract public function someMethod2($name, $color);
  abstract public function someMethod3() : string;
}
?>

PHP – Interfaces

Interfaces allow you to specify what methods a class should implement.

Interfaces make it easy to use a variety of different classes in the same way. When one or more classes use the same interface, it is referred to as “polymorphism”.

Some important learning aspects from today’s day:

Revised basic PHP functions and methods
Read about Classes, Inheritance & Interfaces

Need to work more on:

Interfaces

That’s pretty much how my day today went at rtCamp, looking towards more wonderful days.

Regards

–

Aryan Jasala

WordPress Engineer Trainee

PHP