what is php

php 

features

simpler to learn and easier to implement (good news to learner)

it can work faster

highly flexible ( changes can be done without developers intevention)

platform indepedent( any platform can work)

interpreted ( does  not need to be compiled)

open source

dynamic webpages

securiety encryption

cost effiecient

work with so many databases

it can run on any enviroment

it is old languagte and it has large community support

80 % web is stilll powered by php

wordpress

shopify

opencart

magento, joomla, drupal, wix, square space

presta shop

laravel

codeignitor

zend framweork

symfony

cakephp

yii framwework

 https://youtu.be/6EukZDFE_Zg

php stands for 

hyper text pre processor

it is an opensource serer side scripting  language

that is embeded into htm and used for webdevelopments

syntax 

<?php ?>

<?php 

echo "hellow wold";

?>

how does php work

BROWSER REQUEST TO SERVER

PHP INTERPERETER 

based on the request, it proceess , it pulls data from databse

developed in php

wordpress,tumblr,yahoo

facebook,wikipedia

we can xampp 

cross platform , apache sereer, mariad db, php, perl

sring

array = 

$laptop =array("hp","lenovo","asus");

comments, multi line comments

var_dump

print_R

echo

concatenate string and varaible, 

define strings , array => declaring constatns

at anny case programm value cannot modify

at any ase value cannot 

if we declare declare(strict_types=1);

define("laptops",["hp","lenovo"]);

echo laptops[2];

task print varaibvle if it si greater than 7

$var = 8;

if($var > 7){

echo $var;

}

else {
}

else is used if condition is not matched

&& and conditon

|| or conditon

($var % 3 ==0)

elseif 

switch() or match

default 

break

case

php loops

for loop

for loop

while loop

as long as conditon true,it loops

while(condition){
executes}

while do (ist excutes then lopo)

do{

executes}

while(conditon){

lop executes}

for(inistialisation,condtion, incrimentafterloop)

ist $is=0,

then condtion check 

then go to inside

then postincriment

then condtion

then loo

\

inbuilt functions

echo (var,string,object,array)

function user defined

some time some code is repeating, we will call this function where ever require

if we dont call, length of code increases

oops conspts in php

class 

object

constructor 

destructior

inheritance

polymorphism

public 

private 

protected

instance 

static => ::

class fruit {

public $name;

public $color;

function set_name($name){

$this->name=$name;

}

function get_name(){

$this->name;

}

}

$apple =new fruit(); it is object or instance

 car is class 

bmw is object 

objectsa re calusing new 

bmw is properites

every objects has properties and functoins

member vraibles 

member functions

function __construct(){

}

function __destruct(){

private upto that class

protected upto child but can acess from public function

 inherited or derived or extends ( inherited calsas can access all properties and functons of parent class)

echo "s {$this->name} 

polymorphism( same function in parent and child and if we call child class,  it executes child functions only if have same funciton name, ist child then parent )

vs code extensions

php intellipehnce

giving suggestioins for the params 

php mess detector 

error detecting  analys code

auto close tag

it will call close end tag automaticlyy

phpfmt php formaterr

clean indentation

php debug

to debug errors

xdebug .org

get and post in php

get is encode user information with question mark in url 

it si restriction if sending up to 1024 cjaracters 

dont share confidential infromation using get

in server logs=>it builds a long string

get cannot besued to share images or word cdocumetn to the server

data sent by get method can be accesses using query_string environment varaible

<?pohp 

if isset($_GET['NAME]) || isset($_GET{'AGE']){

exit();

$_PHP_SELF => SAME URL

POST METHOD

its sends via http headers

no restriction on datasize to be sent

it sends ascii as well as images and documents

security

if(isset($_+POST{'NAME]) || isset($_post['age'){

$_request['name')

$_SERVER['REQUEST_METHOD']=='POST'

post is

php development career road map

udemy, youtube

any development career is good starts  is good

php is using start up companies ( after 2 year realtime experience )

html ,css,js it is plus

databse is plus

php with my sql

https://www.computerhope.com/htmcolor.htm

<body bgcolor="colorcode">

</body>

php form validations

IF(empty($_post['name']

test_input($_post['name];

trim

stripslashes

htmlspecialchars

database file

include config.php

if isset $_post['submit']

create

select

if($resilt->num_rows>0

while ($row= $result->fetch_Assoc(){

update

database

session_Start();

session_unset();

session_Destroy();

header{'location:index.php);

rest api

cient to server

stateless

cacheable

uniform interface

layered sstem 

code on demand

it uses http method (crud)

mysqli_Select_Db($con,$photography)

my_Variable

variable starts with undescore or leter

$My__Varaible

popular phgp frameword

isset()

definaed varaible that has value or not

objects in pph 

new fruit();

display outpyt in browser

<?=  ?>

define  declared cosntatnt

$vairalbge

simple variable

$$varaible => variabel of variables

fianl class s

its class cannot extended

it cannot be ovverridden

over loading 

same function repeated in same calss

overl riding

same function in parent and child clas

php accepts riding not overloading

== and ===

type and value

how does exception handling work in php

require and include

require -==> file not found throw error, stops execution

include => file not found, produce warning, execute remaingn script

types of error 

notice

warning

fatal

how to call a function by referecnce

single ton clas in php

that have only one object 

encrypt a password using php

sort,rsort,asort,ksort,arsort,krsort

what is the output of following cocde

php and javascript interact

explain typehinting is php

if datatype is not matched , it wills how error

wrte a class to solve the following question

https://www.youtube.com/watch?time_continue=22941&v=6EukZDFE_Zg&embeds_referring_euri=https%3A%2F%2Flearntube.ai%2F&embeds_referring_origin=https%3A%2F%2Flearntube.ai&source_ve_path=MTI3Mjk5LDEyNzI5OSwyODY2MywzNjg0MiwyODY2Ng&feature=emb_logo

php syntax

<?php 

echo "h";

?>

php varaibles

modify varibble data type by storing resepective data

const pi =3.14

php echo /print

echo "html;" tags;

print"html tags";

both are same

tasks 

Question

In this task, you have to create a variable following the proper PHP syntax and give it the value “Learning PHP from LearnTube”. Print the variable created in the output. 

Description

Step 1: To work on the given task you can do it from the xampp server in your local machine or try any online php compiler.

Step 2: Write the code for the given program and run it.

Program:
<?php
$txt = "Learning PHP from LearnTube";

echo $txt;
?>

Step 3: Share your code in a google doc and a screenshot of the final result in PNG format by clicking on the "Upload Here" Button.

== 

php strings 

difference between double quoites and signle quoites

'single quote'

'single \' quote'

"double {} quotes"

In PHP, there are two primary ways to specify string literals: using double quotes (" ") and single quotes (' '). Here are the key differences between them:

1. Variable Parsing:

   • Double quotes allow variable parsing, meaning that variables and escape sequences inside the string are interpreted and replaced with their values. For example:

     php
     $name = "John";
     echo "Hello, $name!"; // Outputs: Hello, John!
     

   • Single quotes do not perform variable parsing. They treat everything inside them as a literal string, including variables and escape sequences. For example:

     php
     $name = "John";
     echo 'Hello, $name!'; // Outputs: Hello, $name!
     

2. Escape Sequences:

   • Both double quotes and single quotes support escape sequences, such as \n for newline, \t for tab, \" for double quote, \\ for backslash, etc.
   • However, when using double quotes, escape sequences are interpreted and replaced with their actual characters. In single quotes, escape sequences are treated literally.

     php
     echo "Hello\nWorld"; // Outputs:
                           // Hello
                           // World
     
     echo 'Hello\nWorld'; // Outputs: Hello\nWorld
     

3. Performance:

   • Single quotes are slightly faster than double quotes because they don't involve variable parsing or interpreting escape sequences.
   • However, the performance difference is often negligible in most PHP applications unless you're dealing with a massive number of string operations.

4. Use Case:

   • Double quotes are commonly used when you need to include variables or escape sequences within the string.
   • Single quotes are useful for string literals that don't require variable interpolation or where you want to ensure that special characters are treated literally.

inteface example 

php numbers

https://www.youtube.com/watch?v=2eebptXfEvw&t=1571s

php super globals

$GLOBALS

$_POST

$_GET

$_COOKIE

$_SESSION

DIFFERENCE BETWEEN COOKIE AND SESSION

Sessions and cookies are both mechanisms used in web development to store information and maintain state across multiple HTTP requests. However, they differ in several key aspects:

1. Storage Location:

   • Session: Session data is stored on the server. The client (browser) receives a session ID, typically in the form of a cookie, which is used to identify the session data stored on the server.
   • Cookie: Cookies are small pieces of data sent from a website and stored in the user's browser. They are primarily used for client-side storage.

2. Lifetime:

   • Session: Session data typically lasts for the duration of a user's visit to a website. When the user closes the browser or the session expires due to inactivity, the session data is usually destroyed.
   • Cookie: Cookies can have different lifetimes. They can be session cookies (deleted when the browser is closed) or persistent cookies (stored on the user's device for a specified period or until manually deleted).

3. Data Storage:

   • Session: Sessions can store more data compared to cookies because the data is stored on the server. This makes sessions suitable for storing sensitive or larger amounts of data.
   • Cookie: Cookies have size limitations (commonly around 4KB per cookie). They are generally used to store smaller amounts of data, such as user preferences, authentication tokens, or tracking information.

4. Access:

   • Session: Session data is accessible on the server-side. In PHP, for example, session data can be accessed using $_SESSION superglobal.
   • Cookie: Cookies are accessible on the client-side (browser). JavaScript and server-side scripting languages like PHP can access cookies, but the data is stored on the client's browser.

5. Security:

   • Session: Session data is typically more secure than cookies because it is stored on the server. However, sessions are still vulnerable to session hijacking or fixation attacks if not implemented securely.
   • Cookie: Cookies can pose security risks, such as cross-site scripting (XSS) and cross-site request forgery (CSRF), if not used and managed properly. Secure and HTTP-only flags can be set to enhance cookie security.

In summary, sessions are more secure and suitable for storing sensitive or larger amounts of data on the server-side, while cookies are commonly used for smaller data storage and client-side operations like maintaining user preferences and tracking user activity. The choice between sessions and cookies depends on the specific requirements and security considerations of the web application.

===

REGESX

PREG_MATCH

PREG_REPLACE

 

REQUIRE_ONCE

RUN PHP IN TERMINAL php 

inteface 

transversable

 

construct write after ddevclaring variables

=

top 10reasons to learn php

so many websites using php

its easy to learn

opn source 

frameworks (its easy to build large applicaton)

cross platform ( linux, mac, windows)

multi databse (mysql ..)

php sacalabilty ( if u wann change to large scale)

community ( biggest community)

check last update

job market

why php is still so important for webdevelopment

accoirding to survey report form w3techs.com

10 million plus website using php