Points of PHP

Syntax

PHP Code

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<?php
    ...
?>

Note All statements end with a semicolon ;
Note Everything except variable names are NOT case sensitive.

Comments

// and # are used for single-line comment
/* ... */ can be used for multi-line comment

Variables

Usage

$variable_name = "anything"

Note: PHP is a loosely typed language

Scope

• local
• global
• static

Global

global keyword can be used to make variable global.
$GLOBALs['index'] can be used to access global variables.

Static

Static variable is local. It won’t be deleted when function completed.
static keyword can be used to make variable static.

Constant

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define("SHI", "Hello world!"[, case_insensitive = false]);
echo SHI;

Data Type

var_dump($x); can be used to show the type of a variable.

String

Variables can be integrated directly into strings:

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echo "<h1>$txt</h1>";

Note: echo and print can be used with or without parentheses

. can be used to concatenate strings.
.= to append.

Array

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$a = array(1, 2, 3);
$a[0];

$b = array("a"=>1, "b"=>2, "c"=>3);
$b['a'];
foreach($b as $bi => $bi_value) {
    echo "Key=" . $bi . ", Value=" . $bi_value;
}

Function

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function fu($a, $b=0) {
    ...
    return 0
}

Object

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class Bi {
    function Bi(){
        $this->shi = "shi";
    }
}

// Create an object
$b = new Bi();

echo $b->shi;

Condition Statement

If

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if() {
    ...
} elseif() {
    ...
} else{
    ...
}

Switch

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switch (n) {
    case label1:
        ...
        break;
    ...
    default:
        ...
}

Loops

While

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while() {
    ...
}

do {
    ...
} while();

For

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for(...;...;...) {
    ...
}

for ($i as $arr) {
    ...
}

Skills

Redirection

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header("Location: ".$url, true, $permanent ? 301 : 302);
die();