PHP-Practice-files/PHP Basic.txt at main · CodeCrafter103/PHP-Practice-files · GitHub

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//print
<?php
$txt = "PHP";
echo "I love $txt!";
?>

//version cheek
echo phpversion();

//syntax
<?php
// PHP code goes here
?>

//simple php file
<!DOCTYPE html>
<html>
<body>

<h1>My first PHP page</h1>

<?php
echo "Hello World!";
?>

</body>

//PHP Case Sensitivity
<!DOCTYPE html>
<html>
<body>

<?php
ECHO "Hello World!<br>"; // EcHo and echo treated differently
echo "Hello World!<br>";
EcHo "Hello World!<br>";
?>

</body>
</html>

//$COLOR is not same as $color
<!DOCTYPE html>
<html>
<body>

<?php
$color = "red";
echo "My car is " . $color . "<br>";
echo "My house is " . $COLOR . "<br>";
echo "My boat is " . $coLOR . "<br>";
?>

</body>
</html>

//Comment
// This is a single-line comment

# This is also a single-line comment

/* This is a
multi-line comment */

//variable
$x = 5;//integer type
$y = "John";//string

//output of the variable inside text
$txt = "W3Schools.com";
echo "I love $txt!";

//summation of two value
$x = 5;
$y = 4;
echo $x + $y;

//Add two different variable of not same type
$x = 5;      // $x is an integer
$y = "John"; // $y is a string
echo $x;
echo $y;

#cheek datatype of variable by var_dump() function
var_dump(5);//int
var_dump("John");//string
var_dump(3.14);//float
var_dump(true);//boolean
var_dump([2, 3, 56]);//array make in form of associative array
var_dump(NULL);//Null type

//Assign Multiple Values
$x = $y = $z = "Fruits"

$x = 5; // global scope

//Global scope
function myTest() {
  // using x inside this function will generate an error
  echo "<p>Variable x inside function is: $x</p>"; //No output
}
myTest();//5

echo "<p>Variable x outside function is: $x</p>";

//Local scope
function myTest() {
  $x = 5; // local scope
  echo "<p>Variable x inside function is: $x</p>";//5
}
myTest();

// using x outside the function will generate an error
echo "<p>Variable x outside function is: $x</p>";//No output

echo "Hello";
//same as:
echo("Hello") but it is a function;//without parentheses

//Print by different styling way..
echo "<h2>PHP is Fun!</h2>";
echo "Hello world!<br>";
echo "I'm about to learn PHP!<br>";
echo "This ", "string ", "was ", "made ", "with multiple parameters.";

//Display text and varriable together
$txt1 = "Learn PHP";
$txt2 = "W3Schools.com";

echo "<h2>$txt1</h2>";
echo "<p>Study PHP at $txt2</p>";

//array
$cars = array("Volvo","BMW","Toyota");
var_dump($cars);

//class sample basic
class Car {
  public $color;
  public $model;
  public function __construct($color, $model) {
    $this->color = $color;
    $this->model = $model;
  }
  public function message() {
    return "My car is a " . $this->color . " " . $this->model . "!";
  }
}

$myCar = new Car("red", "Volvo");
var_dump($myCar);

//single qotes and double
echo "Hello";
echo 'Hello';

//double qotes in text print
$x = "John";
echo "Hello $x";

//Length of string
echo strlen("Hello world!");===> strlen()

//Word count*
echo str_word_count("Hello world!");==> str_word_count()

//specific text within a string
echo strpos("Hello world!", "world");

//strtoupper()
$x = "Hello World!";
echo strtoupper($x);

//strtolower()
$x = "Hello World!";
echo strtolower($x);

//Replace String
$x = "Hello World!";
echo str_replace("World", "Dolly", $x);

//Reverse a String
$x = "Hello World!";
echo strrev($x);

//Remove Whitespace
$x = " Hello World! ";
echo trim($x);

Convert String into Array by explode() function
$x = "Hello World!";
$y = explode(" ", $x);

//Use the print_r() function to display the result:
print_r($y);

/*
Result:
Array ( [0] => Hello [1] => World! )
*/

//String Concatenation
$x = "Hello";
$y = "World";
$z = $x . " " . $y;
echo $z;

//Slicing string by substr function
$x = "Hello World!";
echo substr($x, 6, 5);
echo substr($x, 6);
echo substr($x, -5, 3);
echo substr($x, 5, -3);

//Escape character-> \
$x = "We are the so-called \"Vikings\" from the north.";
Example:-
\'	Single Quote
\"	Double Quote
\$	PHP variables
\n	New Line
\r	Carriage Return
\t	Tab
\f	Form Feed
\ooo	Octal value
\xhh	Hex value

//Check if the type of a variable is integer
$x = 5985;
var_dump(is_int($x));

$x = 59.85;
var_dump(is_int($x));

$x = 10.365;
var_dump(is_float($x));

$x = 1.9e411;
var_dump($x);

$x = acos(8);
var_dump($x);

//Check if the variable is numeric

$x = 5985;
var_dump(is_numeric($x));

$x = "5985";
var_dump(is_numeric($x));
$x = "59.85" + 100;
var_dump(is_numeric($x));

$x = "Hello";
var_dump(is_numeric($x));

//Cast float and string to integer typecasting

// Cast float to int
$x = 23465.768;
$int_cast = (int)$x;
echo $int_cast;

echo "<br>";

// Cast string to int
$x = "23465.768";
$int_cast = (int)$x;
echo $int_cast;

//typecasting
$a = 5;       // Integer
$b = 5.34;    // Float
$c = "hello"; // String
$d = true;    // Boolean
$e = NULL;    // NULL

$a = (string) $a;
$b = (string) $b;
$c = (string) $c;
$d = (string) $d;
$e = (string) $e;

//To verify the type of any object in PHP, use the var_dump() function:
var_dump($a);
var_dump($b);
var_dump($c);
var_dump($d);
var_dump($e);

//pi() Function
echo(pi());

//min() and max() Functions
echo(min(0, 150, 30, 20, -8, -200));
echo(max(0, 150, 30, 20, -8, -200));

//abs function
echo(abs(-6.7));

//sqrt() Function
echo(sqrt(64));

//round() Function
echo(round(0.60));
echo(round(0.49));

//rand function
rand()->random number
echo(rand(10, 100));

//Constant operation by define()
define(name, value);
//Example
define("GREETING", "Coder Hub by Om!");
echo GREETING;

const MYCAR = "Volvo";
echo MYCAR;

//constant arrays
define("cars", [
  "Alfa Romeo",
  "BMW",
  "Toyota"
]);
echo cars[0];

//As function
define("GREETING", "Coder Hub by Om!");

function myTest() {
  echo GREETING;
}

myTest();

//Magic Constants

Constant	Description
__CLASS__	If used inside a class, the class name is returned.
__DIR__	The directory of the file.
__FILE__	The file name including the full path.
__FUNCTION__	If inside a function, the function name is returned.
__LINE__	The current line number.
__METHOD__	If used inside a function that belongs to a class, both class and function name is returned.
__NAMESPACE__	If used inside a namespace, the name of the namespace is returned.
__TRAIT__	If used inside a trait, the trait name is returned.
ClassName::class	Returns the name of the specified class and the name of the namespace, if any.

//PHP Arithmetic Operators
The PHP arithmetic operators are used with numeric values to perform common arithmetical operations, such as addition, subtraction, multiplication etc.

Operator	Name	Example	Result	Try it
+	Addition	$x + $y	Sum of $x and $y
-	Subtraction	$x - $y	Difference of $x and $y
*	Multiplication	$x * $y	Product of $x and $y
/	Division	$x / $y	Quotient of $x and $y
%	Modulus	$x % $y	Remainder of $x divided by $y
**	Exponentiation	$x ** $y	Result of raising $x to the $y'th pow

PHP Assignment Operators
The PHP assignment operators are used with numeric values to write a value to a variable.

The basic assignment operator in PHP is "=". It means that the left operand gets set to the value of the assignment expression on the right.

Assignment	Same as...	Description	Try it
x = y	x = y	The left operand gets set to the value of the expression on the right
x += y	x = x + y	Addition
x -= y	x = x - y	Subtraction
x *= y	x = x * y	Multiplication
x /= y	x = x / y	Division
x %= y	x = x % y	Modulus

The PHP comparison operators are used to compare two values (number or string):

Operator	Name	Example	Result	Try it
==	Equal	$x == $y	Returns true if $x is equal to $y
===	Identical	$x === $y	Returns true if $x is equal to $y, and they are of the same type
!=	Not equal	$x != $y	Returns true if $x is not equal to $y
<>	Not equal	$x <> $y	Returns true if $x is not equal to $y
!==	Not identical	$x !== $y	Returns true if $x is not equal to $y, or they are not of the same type
>	Greater than	$x > $y	Returns true if $x is greater than $y
<	Less than	$x < $y	Returns true if $x is less than $y
>=	Greater than or equal to	$x >= $y	Returns true if $x is greater than or equal to $y
<=	Less than or equal to	$x <= $y	Returns true if $x is less than or equal to $y
<=>	Spaceship	$x <=> $y	Returns an integer less than, equal to, or greater than zero, depending on if $x is less than, equal to, or greater than $y. Introduced in PHP 7.

PHP Increment / Decrement Operators
The PHP increment operators are used to increment a variable's value.

The PHP decrement operators are used to decrement a variable's value.

Operator	Same as...	Description	Try it
++$x	Pre-increment	Increments $x by one, then returns $x
$x++	Post-increment	Returns $x, then increments $x by one
--$x	Pre-decrement	Decrements $x by one, then returns $x
$x--	Post-decrement	Returns $x, then decrements $x by one

PHP Logical Operators
The PHP logical operators are used to combine conditional statements.

Operator	Name	Example	Result	Try it
and	And	$x and $y	True if both $x and $y are true
or	Or	$x or $y	True if either $x or $y is true
xor	Xor	$x xor $y	True if either $x or $y is true, but not both
&&	And	$x && $y	True if both $x and $y are true
||	Or	$x || $y	True if either $x or $y is true
!	Not	!$x	True if $x is not true

PHP String Operators
PHP has two operators that are specially designed for strings.

Operator	Name	Example	Result	Try it
.	Concatenation	$txt1 . $txt2	Concatenation of $txt1 and $txt2
.=	Concatenation assignment	$txt1 .= $txt2	Appends $txt2 to $txt1

PHP Array Operators
The PHP array operators are used to compare arrays.

Operator	Name	Example	Result	Try it
+	Union	$x + $y	Union of $x and $y
==	Equality	$x == $y	Returns true if $x and $y have the same key/value pairs
===	Identity	$x === $y	Returns true if $x and $y have the same key/value pairs in the same order and of the same types
!=	Inequality	$x != $y	Returns true if $x is not equal to $y
<>	Inequality	$x <> $y	Returns true if $x is not equal to $y
!==	Non-identity	$x !== $y	Returns true if $x is not identical to $y

HP Conditional Assignment Operators
The PHP conditional assignment operators are used to set a value depending on conditions:

Operator	Name	Example	Result	Try it
?:	Ternary	$x = expr1 ? expr2 : expr3	Returns the value of $x.
The value of $x is expr2 if expr1 = TRUE.
The value of $x is expr3 if expr1 = FALSE
??	Null coalescing	$x = expr1 ?? expr2	Returns the value of $x.
The value of $x is expr1 if expr1 exists, and is not NULL.
If expr1 does not exist, or is NULL, the value of $x is expr2.
Introduced in PHP 7

PHP Conditional Statements
Very often when you write code, you want to perform different actions for different conditions. You can use conditional statements in your code to do this.

//In PHP we have the following conditional statements:

if statement - executes some code if one condition is true
if...else statement - executes some code if a condition is true and another code if that condition is false
if...elseif...else statement - executes different codes for more than two conditions
switch statement - selects one of many blocks of code to be executed

PHP - The if Statement
The if statement executes some code if one condition is true.

Syntax
if (condition) {
  // code to be executed if condition is true;
}

//Example
if (5 > 3) {
  echo "Have a good day!";
}

$t = 14;

if ($t < 20) {
  echo "Have a good day!";
}

//Check if $t is equal to 14:

$t = 14;

if ($t == 14) {
  echo "Have a good day!";
}

Logical Operators
To check more than one condition, we can use logical operators, like the && operator:

Example
//Check if $a is greater than $b, AND if $a is less than $c:

$a = 200;
$b = 33;
$c = 500;

if ($a > $b && $a < $c ) {
  echo "Both conditions are true";
}

//Check if $a is either 2, 3, 4, 5, 6, or 7:

$a = 5;

if ($a == 2 || $a == 3 || $a == 4 || $a == 5 || $a == 6 || $a == 7) {
  echo "$a is a number between 2 and 7";
}

//If and Else
PHP - The if...else Statement
The if...else statement executes some code if a condition is true and another code if that condition is false.

Syntax
if (condition) {
  // code to be executed if condition is true;
} else {
  // code to be executed if condition is false;
}

$t = date("H");

if ($t < "20") {
  echo "Have a good day!";
} else {
  echo "Have a good night!";
}

//PHP - The if...elseif...else Statement
The if...elseif...else statement executes different codes for more than two conditions.

Syntax
if (condition) {
  code to be executed if this condition is true;
} elseif (condition) {
  // code to be executed if first condition is false and this condition is true;
} else {
  // code to be executed if all conditions are false;
}

$t = date("H");

if ($t < "10") {
  echo "Have a good morning!";
} elseif ($t < "20") {
  echo "Have a good day!";
} else {
  echo "Have a good night!";
}

//Short Hand If
$a = 5;

if ($a < 10) $b = "Hello";

echo $b

$a = 13;

$b = $a < 10 ? "Hello" : "Good Bye";

echo $b;

//Nested If
$a = 13;

if ($a > 10) {
  echo "Above 10";
  if ($a > 20) {
    echo " and also above 20";
  } else {
    echo " but not above 20";
  }
}

//The PHP switch Statement
Use the switch statement to select one of many blocks of code to be executed.

Syntax
switch (expression) {
  case label1:
    //code block
    break;
  case label2:
    //code block;
    break;
  case label3:
    //code block
    break;
  default:
    //code block
}

$favcolor = "red";

switch ($favcolor) {
  case "red":
    echo "Your favorite color is red!";
    break;
  case "blue":
    echo "Your favorite color is blue!";
    break;
  case "green":
    echo "Your favorite color is green!";
    break;
  default:
    echo "Your favorite color is neither red, blue, nor green!";
}

//PHP Loops
Often when you write code, you want the same block of code to run over and over again a certain number of times. So, instead of adding several almost equal code-lines in a script, we can use loops.

Loops are used to execute the same block of code again and again, as long as a certain condition is true.

In PHP, we have the following loop types:

while - loops through a block of code as long as the specified condition is true
do...while - loops through a block of code once, and then repeats the loop as long as the specified condition is true
for - loops through a block of code a specified number of times
foreach - loops through a block of code for each element in an array

Print $i as long as $i is less than 6:

$i = 1;
while ($i < 6) {
  echo $i;
  $i++;
}

$i = 1;
while ($i < 6) {
  if ($i == 3) break;
  echo $i;
  $i++;
}

$i = 0;
while ($i < 6) {
  $i++;
  if ($i == 3) continue;
  echo $i;
}

$i = 1;
while ($i < 6):
  echo $i;
  $i++;
endwhile;

$i = 0;
while ($i < 100) {
  $i+=10;
  echo $i "<br>";
}

$i = 1;

do {
  echo $i;
  $i++;
} while ($i < 6);

$i = 8;

do {
  echo $i;
  $i++;
} while ($i < 6);

$i = 0;

do {
  $i++;
  if ($i == 3) continue;
  echo $i;
} while ($i < 6);

//The PHP for Loop
The for loop is used when you know how many times the script should run.

Syntax
for (expression1, expression2, expression3) {
  // code block
}

for ($x = 0; $x <= 10; $x++) {
  echo "The number is: $x <br>";
}

for ($x = 0; $x <= 10; $x++) {
  if ($x == 3) break;
  echo "The number is: $x <br>";
}

for ($x = 0; $x <= 10; $x++) {
  if ($x == 3) continue;
  echo "The number is: $x <br>";
}

for ($x = 0; $x <= 100; $x+=10) {
  echo "The number is: $x <br>";
}

//PHP foreach Loop
$colors = array("red", "green", "blue", "yellow");

foreach ($colors as $x) {
  echo "$x <br>";
}

$members = array("Peter"=>"35", "Ben"=>"37", "Joe"=>"43");

foreach ($members as $x => $y) {
  echo "$x : $y <br>";
}

$colors = array("red", "green", "blue", "yellow");

foreach ($colors as $x) {
  if ($x == "blue") break;
  echo "$x <br>";
}

$colors = array("red", "green", "blue", "yellow");

foreach ($colors as $x) {
  if ($x == "blue") continue;
  echo "$x <br>";
}$colors = array("red", "green", "blue", "yellow");

foreach ($colors as $x) {
  if ($x == "blue") $x = "pink";
}

var_dump($colors);

$colors = array("red", "green", "blue", "yellow");

foreach ($colors as &$x) {
  if ($x == "blue") $x = "pink";
}

var_dump($colors);

$colors = array("red", "green", "blue", "yellow");

foreach ($colors as $x) :
  echo "$x <br>";
endforeach;

//Break in For loop
for ($x = 0; $x < 10; $x++) {
  if ($x == 4) {
    break;
  }
  echo "The number is: $x <br>";
}

$x = 0;

while($x < 10) {
  if ($x == 4) {
    break;
  }
  echo "The number is: $x <br>";
  $x++;
}

$i = 1;

do {
  if ($i == 3) break;
  echo $i;
  $i++;
} while ($i < 6);

$colors = array("red", "green", "blue", "yellow");

foreach ($colors as $x) {
  if ($x == "blue") break;
  echo "$x <br>";
}

//Continue in For Loops
for ($x = 0; $x < 10; $x++) {
  if ($x == 4) {
    continue;
  }
  echo "The number is: $x <br>";
}

$x = 0;

while($x < 10) {
  if ($x == 4) {
    continue;
  }
  echo "The number is: $x <br>";
  $x++;
}

$i = 0;

do {
  $i++;
  if ($i == 3) continue;
  echo $i;
} while ($i < 6);

$colors = array("red", "green", "blue", "yellow");

foreach ($colors as $x) {
  if ($x == "blue") continue;
  echo "$x <br>";
}

//PHP Functions
function myMessage() {
  echo "Hello world!";
}

function myMessage() {
  echo "Hello world!";
}

myMessage();

function familyName($fname) {
  echo "$fname Refsnes.<br>";
}

familyName("Jani");
familyName("Hege");
familyName("Stale");
familyName("Kai Jim");
familyName("Borge")

function familyName($fname, $year) {
  echo "$fname Refsnes. Born in $year <br>";
}

familyName("Hege", "1975");
familyName("Stale", "1978");
familyName("Kai Jim", "1983");

function setHeight($minheight = 50) {
  echo "The height is : $minheight <br>";
}

setHeight(350);
setHeight(); // will use the default value of 50
setHeight(135);
setHeight(80);

function sum($x, $y) {
  $z = $x + $y;
  return $z;
}

echo "5 + 10 = " . sum(5, 10) . "<br>";
echo "7 + 13 = " . sum(7, 13) . "<br>";
echo "2 + 4 = " . sum(2, 4);

function add_five(&$value) {
  $value += 5;
}

$num = 2;
add_five($num);
echo $num;

function sumMyNumbers(...$x) {
  $n = 0;
  $len = count($x);
  for($i = 0; $i < $len; $i++) {
    $n += $x[$i];
  }
  return $n;
}

$a = sumMyNumbers(5, 2, 6, 2, 7, 7);
echo $a;

function myFamily($lastname, ...$firstname) {
  $txt = "";
  $len = count($firstname);
  for($i = 0; $i < $len; $i++) {
    $txt = $txt."Hi, $firstname[$i] $lastname.<br>";
  }
  return $txt;
}

$a = myFamily("Doe", "Jane", "John", "Joey");
echo $a;

function addNumbers(int $a, int $b) {
  return $a + $b;
}
echo addNumbers(5, "5 days");
// since strict is NOT enabled "5 days" is changed to int(5), and it will return 10

//strict_types enabled
<?php declare(strict_types=1); // strict requirement
function addNumbers(float $a, float $b) : float {
  return $a + $b;
}
echo addNumbers(1.2, 5.2);
?>

<?php declare(strict_types=1); // strict requirement
function addNumbers(float $a, float $b) : int {
  return (int)($a + $b);
}
echo addNumbers(1.2, 5.2)

//Array to be continue...
$cars = array("Volvo", "BMW", "Toyota");
An array stores multiple values in one single variable..

PHP Array Types
In PHP, there are three types of arrays:

Indexed arrays - Arrays with a numeric index
Associative arrays - Arrays with named keys
Multidimensional arrays - Arrays containing one or more arrays

Array items of four different data types:
$myArr = array("Volvo", 15, ["apples", "bananas"], myFunction);

Array Functions:-
$cars = array("Volvo", "BMW", "Toyota");
echo count($cars);

//PHP Indexed Arrays
$cars = array("Volvo", "BMW", "Toyota");
var_dump($cars);

//Access Indexed Arrays
$cars = array("Volvo", "BMW", "Toyota");
echo $cars[0];

//Change Value
$cars = array("Volvo", "BMW", "Toyota");
$cars[1] = "Ford";
var_dump($cars);

//Loop Through an Indexed Array
$cars = array("Volvo", "BMW", "Toyota");
foreach ($cars as $x) {
  echo "$x <br>";
}

//PHP Associative Arrays
Associative arrays are arrays that use named keys that you assign to them as a given value.

$car = array("brand"=>"Ford", "model"=>"Mustang", "year"=>1964);
var_dump($car);

//Access Associative Arrays

$car = array("brand"=>"Ford", "model"=>"Mustang", "year"=>1964);
echo $car["model"];

//Change Value
$car = array("brand"=>"Ford", "model"=>"Mustang", "year"=>1964);
$car["year"] = 2024;
var_dump($car);

//Loop Through an Associative Array
$car = array("brand"=>"Ford", "model"=>"Mustang", "year"=>1964);

foreach ($car as $x => $y) {
  echo "$x: $y <br>";
}

//PHP Global Variables - Superglobals
Some predefined variables in PHP are "superglobals", which means that they are always accessible, regardless of scope - and you can access them from any function, class or file without having to do anything special.

The PHP superglobal variables are:

$GLOBALS
$_SERVER
$_REQUEST
$_POST
$_GET
$_FILES
$_ENV
$_COOKIE
$_SESSION

//$_REQUEST
$_REQUEST is a PHP super global variable which contains submitted form data, and all cookie data.

In other words, $_REQUEST is an array containing data from $_GET, $_POST, and $_COOKIE.

You can access this data with the $_REQUEST keyword followed by the name of the form field, or cookie, like this:

$_REQUEST['firstname']

<html>
<body>

<form method="post" action="demo_request.php">
  Name: <input type="text" name="fname">
  <input type="submit">
</form>

</body>
</html>