Curriculum

PHP Basic

PHP Intro

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PHP Install

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PHP Syntax

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PHP Comments

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PHP Variables

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PHP echo / print

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PHP Data Types

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PHP Strings

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PHP Numbers

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PHP Casting

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PHP Math

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PHP Constants

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PHP Magic Constants

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PHP Operators

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PHP if...Else...Elseif

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PHP switch

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PHP Loops

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PHP Functions

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PHP Arrays

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PHP Superglobals

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PHP RegEx

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PHP Form

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PHP Advanced

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PHP OOP

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MySQL Database

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PHP XML

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PHP Reference

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Text lesson

PHP Filters Advanced

Validate an Integer Within a Range

The following example uses the filter_var() function to check if a variable is of type INT and within the range of 1 to 200:

Example

<?php
$int = 122;
$min = 1;
$max = 200;

if (filter_var($int, FILTER_VALIDATE_INT, array(“options” => array(“min_range”=>$min, “max_range”=>$max))) === false) {
echo(“Variable value is not within the legal range”);
} else {
echo(“Variable value is within the legal range”);
}
?>

Validate IPv6 Address

The following example uses the filter_var() function to verify if the variable $ip is a valid IPv6 address:

Example

<?php
$ip = “2001:0db8:85a3:08d3:1319:8a2e:0370:7334”;

if (!filter_var($ip, FILTER_VALIDATE_IP, FILTER_FLAG_IPV6) === false) {
echo(“$ip is a valid IPv6 address”);
} else {
echo(“$ip is not a valid IPv6 address”);
}
?>

Validate URL – Must Contain QueryString

The following example uses the filter_var() function to determine if the variable $url is a URL that includes a query string:

Example

<?php
$url = “https://www.w3schools.com”;

if (!filter_var($url, FILTER_VALIDATE_URL, FILTER_FLAG_QUERY_REQUIRED) === false) {
echo(“$url is a valid URL with a query string”);
} else {
echo(“$url is not a valid URL with a query string”);
}
?>

Remove Characters With ASCII Value > 127

The following example uses the filter_var() function to sanitize a string by removing all HTML tags and any characters with an ASCII value greater than 127:

Example

<?php
$str = “<h1>Hello WorldÆØÅ!</h1>”;

$newstr = filter_var($str, FILTER_SANITIZE_STRING, FILTER_FLAG_STRIP_HIGH);
echo $newstr;
?>

Complete PHP Filter Reference

For a comprehensive guide to all filter functions, visit our complete PHP Filter Reference.

It details the options and flags available for each filter and includes brief descriptions and usage examples for each function!