PHP¶

Presentation

What is PHP ?¶

PHP, which stands for "PHP: Hypertext Preprocessor" is a widely-used Open Source general-purpose scripting language that is especially suited for web development and can be embedded into HTML. It is an interpreted language, i.e. there is no need for compilation.

Why should you learn PHP ?¶

Multi-purpose language
- Simple websites
- Complex websites
- REST APIs
- Command line scripts
- Image processing
Easy to learn
Easy to set up
Large community
Open source
PHP CMSs
- WordPress
- Drupal
- Magento
PHP Framework
- Laravel
- Symfony
- CodeIgniter
High demand on the job market

Why you should not use PHP ?¶

Building desktop applications
AI and machine learning

PHP syntax¶

Comments¶

<?php

// This is a single line comment

/*
This is a multi-line comment
*/

?>

Variables¶

PHP variables start with a dollar sign $ followed by the name of the variable.

Variable are not typed, i.e. you don't need to specify the type of the variable.

<?php
$name = 'Sophie';
$age = 30;
$isMale = true;
$height = 1.85;
$salary = null;
?>

Strings¶

PHP strings can be defined with single quotes ' or double quotes ".

<?php
// Concatenation
echo 'Hello, my name is ' . $name . ' and I am ' . $age . '.';
echo "Hello, my name is $name and I am $age.";

$name = 'Zeniter';

// String functions
echo strlen($name) . '<br>'; // 7
echo strtoupper($name) . '<br>'; // ZENITER
echo strtolower($name) . '<br>'; // zeniter
echo str_replace('e', 'f', $name) . '<br>'; // Zfnitfr
echo str_replace('t', '', $name) . '<br>'; // Zenier
echo substr($name, 1, 3) . '<br>'; // eni
echo strrev($name) . '<br>'; // retineZ
?>

Numbers¶

PHP numbers can be integers or floats.

<?php
$num = 10;
echo $num . '<br>'; // 10
$num++;
echo $num . '<br>'; // 11
$num--;
echo $num . '<br>'; // 10
$num += 25;
echo $num . '<br>'; // 35
echo abs(-100) . '<br>'; // 100
echo pow(2, 4) . '<br>'; // 16
echo sqrt(144) . '<br>'; // 12

// Order of operations
echo 10 + 3 * 5 . '<br>'; // 25
echo (10 + 3) * 5 . '<br>'; // 65

// Increment / Decrement operators
echo $num++ . '<br>'; // 35
echo ++$num . '<br>'; // 37

// Number functions
echo floor(2.4) . '<br>'; // 2
echo ceil(2.4) . '<br>'; // 3
echo round(2.4) . '<br>'; // 2
echo round(2.6) . '<br>'; // 3
echo round(2.5) . '<br>'; // 3

// Formatting numbers
echo number_format(123456789, 2); // 123,456,789.00

echo is_float(1.25) . '<br>'; // 1
echo is_float(1) . '<br>'; //
echo in_int(1.25) . '<br>'; //

?>

Arrays¶

PHP arrays can be defined with the array() function or with square brackets [].

<?php
// Create an array
$peopleOne = array('Benoîte', 'Monique', 'Sara');
$peopleTwo = ['Benoîte', 'Monique', 'Sara', 'Karen'];
$ages = [20, 30, 40, 50];

// Print the whole array
print_r($peopleOne); // Array ( [0] => Benoîte [1] => Monique [2] => Sara )

// Get element by index
echo $peopleOne[1]; // Monique

// Set element by index
$peopleOne[1] = 'Alice';
echo $peopleOne[1]; // Alice

// Add element
$peopleOne[] = 'Mary';

// Print the whole array
print_r($peopleOne); // Array ( [0] => Benoîte [1] => Alice [2] => Sara [3] => Mary )

// Add element at the beginning of the array
array_unshift($peopleOne, 'Bob');

// Remove element from the end of the array
array_pop($peopleOne);

// Remove element from the beginning of the array
array_shift($peopleOne);

// Split the string into an array
$string = 'Banana,Apple,Peach';
echo $string; // Banana,Apple,Peach
echo '<br>';
$fruits = explode(',', $string);
print_r($fruits); // Array ( [0] => Banana [1] => Apple [2] => Peach )

?>

Booleans¶

PHP booleans can be true or false. They are case insensitive. TRUE, True and true are all valid. 1 is also considered as true and 0 as false. null is considered as false.

<?php
// Create an array
$bool1 = true;
echo 'bool1 : ' . $bool1 . '<br>'; // bool1 : 1

$bool2 = True;
echo 'bool2 : ' . $bool2 . '<br>'; // bool2 : 1

$bool3 = FALSE;
echo 'bool3 : ' . $bool3 . '<br>'; // bool3 : 

$bool4 = false;
echo 'bool4 : ' . $bool4 . '<br>'; // bool4 :
?>

Control structures¶

<?php
// Conditional statements

$num = 4;

if ($num == 5) {
	echo '5 passed';
} elseif ($num == 6) { // you can write elseis
	echo '6 passed';
} else if ($num == 7) { // or else if
	echo '7 passed';
} else {
	echo 'did not pass';
}

// while loop

$num = 0;

while ($num < 10) {
	echo $num;
	echo ' ';
	$num++;
}
// 0 1 2 3 4 5 6 7 8 9

// for loop

for ($i = 0; $i < 10; $i++) {
	echo $i;
	echo ' ';
}
// 0 1 2 3 4 5 6 7 8 9

// foreach loop

$people = ['Virginie', 'Despentes', 'Pénélope', 'Bagieu'];

foreach ($people as $person) {
	echo $person;
	echo ' ';
}
// Virginie Despentes Pénélope Bagieu 