PHP Regular Expressions
Complete Guide in Hindi

<?php
// \d — digits
preg_match("/\d+/", "Order 12345", $m);
echo $m[0]; // 12345

// \w — word characters
preg_match("/\w+/", "Hello World", $m);
echo $m[0]; // Hello

// [aeiou] — vowels
preg_match_all("/[aeiou]/i", "Hello World", $m);
print_r($m[0]); // [e, o, o]

// [^0-9] — non-digits
echo preg_replace("/[^0-9]/", "", "Phone: 9876543210");
// 9876543210
?>

<?php
$html = "<b>Bold</b> and <i>Italic</i>";

// Greedy — maximum match (default)
preg_match("'<.+>'", $html, $m);
echo $m[0]; // <b>Bold</b> and <i>Italic</i> — all!

// Lazy — minimum match (? add करो)
preg_match("'<.+?>'", $html, $m);
echo $m[0]; // <b> — first tag only

// {n} exact count
preg_match("/\d{6}/", "PIN: 110001", $m);
echo $m[0]; // 110001
?>

<?php
// ^ $ — String boundaries
var_dump(preg_match("/^Hello/", "Hello World")); // 1 (true)
var_dump(preg_match("/^World/", "Hello World")); // 0 (false)

// Capture groups — () — $matches में save
preg_match("/(\d{4})-(\d{2})-(\d{2})/", "2025-05-15", $m);
echo $m[0]; // 2025-05-15 (full match)
echo $m[1]; // 2025 (group 1)
echo $m[2]; // 05 (group 2)
echo $m[3]; // 15 (group 3)

// Named groups — (?P<name>pattern)
preg_match("/(?P<year>\d{4})-(?P<month>\d{2})-(?P<day>\d{2})/", "2025-05-15", $m);
echo $m["year"]; // 2025
echo $m["month"]; // 05
echo $m["day"]; // 15

// \b word boundary
preg_match_all("/\bPHP\b/i", "PHP is great. PHPStorm too.", $m);
echo count($m[0]); // 1 — PHP only, not PHPStorm
?>

<?php
// i — case insensitive
preg_match("/php/i", "I love PHP"); // 1 — PHP, php, Php सब match

// m — multiline
$text = "line1\nline2\nline3";
preg_match_all("/^line/m", $text, $m);
echo count($m[0]); // 3 — हर line का start

// s — dotall (. newline भी)
preg_match("/start.+end/s", "start\nmiddle\nend"); // 1

// u — unicode (Hindi support)
preg_match("/^\p{L}+$/u", "राहुल"); // 1 — Unicode letters

// x — extended (readable pattern)
$emailPattern = "/ ^ # Start [a-z0-9._-]+ # Local part @ # @ symbol [a-z0-9.-]+ # Domain \. # Dot [a-z]{2,} # TLD $ # End /ix";
?>

<?php
// Simple check — match है?
if (preg_match("/^\d{10}$/", "9876543210")) {
  echo "✅ Valid 10-digit number";
}

// $matches — captured groups
if (preg_match("/^(\w+)\s(\w+)$/", "Rahul Kumar", $matches)) {
  echo $matches[0]; // "Rahul Kumar" (full)
  echo $matches[1]; // "Rahul" (first name)
  echo $matches[2]; // "Kumar" (last name)
}

// Date extract
$log = "Error at 2025-05-15 14:30:00: Connection failed";
if (preg_match("/(\d{4}-\d{2}-\d{2}) (\d{2}:\d{2}:\d{2})/", $log, $m)) {
  echo "Date: " . $m[1]; // 2025-05-15
  echo "Time: " . $m[2]; // 14:30:00
}
?>

<?php
// सब email addresses extract करो
$text = "Contact us at rahul@gmail.com or support@hnp.in for help.";
$count = preg_match_all("/[a-z0-9._%+-]+@[a-z0-9.-]+\.[a-z]{2,}/i", $text, $matches);
echo "Found $count emails:\n";
print_r($matches[0]); // [rahul@gmail.com, support@hnp.in]

// All prices extract
$prices = "Items: ₹450, ₹799, ₹299, ₹1,299";
preg_match_all("/₹([\d,]+)/", $prices, $m);
print_r($m[1]); // [450, 799, 299, 1,299]

// HTML links extract
$html = '<a href="https://php.net">PHP</a> <a href="https://hnp.in">HNP</a>';
preg_match_all('/href="([^"]+)"/', $html, $m);
print_r($m[1]); // [https://php.net, https://hnp.in]

// Hashtags extract
$post = "Learning #PHP and #MySQL! #HindiNotes";
preg_match_all("/\#(\w+)/", $post, $m);
print_r($m[1]); // [PHP, MySQL, HindiNotes]
?>

<?php
// Simple replace
echo preg_replace("/PHP/i", "Python", "I love PHP!");
// I love Python!

// Multiple spaces → single
echo preg_replace("/\s+/", " ", "Hello World PHP");
// Hello World PHP

// HTML tags remove
echo preg_replace("'<[^>]+>'", "", "<b>Bold</b> text");
// Bold text

// Backreferences — $1, $2
// Date format change: 2025-05-15 → 15/05/2025
echo preg_replace("/(\d{4})-(\d{2})-(\d{2})/", "$3/$2/$1", "2025-05-15");
// 15/05/2025

// Mask phone number: 9876543210 → 98XXXXXX10
echo preg_replace("/(\d{2})\d{6}(\d{2})/", "$1XXXXXX$2", "9876543210");
// 98XXXXXX10

// preg_replace_callback — complex logic
$text = "price: 100, 200, 300";
echo preg_replace_callback("/\d+/", fn($m) => $m[0] * 1.18, $text);
// price: 118, 236, 354 (18% GST add)
?>

<?php
// preg_split — pattern से split (explode का powerful version)
// Multiple delimiters — comma, semicolon, pipe
$str = "PHP, MySQL; Laravel | React";
$parts = preg_split("/[,;|]\s*/", $str);
print_r($parts); // [PHP, MySQL, Laravel, React]

// Whitespace split
$words = preg_split("/\s+/", "Hello World PHP");
print_r($words); // [Hello, World, PHP]

// CamelCase को words में split
$camel = "camelCaseVariableName";
$words = preg_split("/(?=[A-Z])/", $camel);
print_r($words); // [camel, Case, Variable, Name]

// preg_grep — array filter with regex
$emails = ["r@gmail.com", "invalid", "p@yahoo.in", "notanemail"];
$valid = preg_grep("/^[a-z0-9.]+@[a-z0-9]+\.[a-z]{2,}$/i", $emails);
print_r($valid); // [r@gmail.com, p@yahoo.in]

// preg_grep — inverse (match नहीं करने वाले)
$invalid = preg_grep("/^[a-z0-9.]+@[a-z0-9]+\.[a-z]{2,}$/i", $emails, PREG_GREP_INVERT);
print_r($invalid); // [invalid, notanemail]
?>

<?php
// Email
$emailPattern = "/^[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}$/";
var_dump(preg_match($emailPattern, "rahul@gmail.com")); // 1

// Indian Mobile — 6-9 से शुरू, 10 digits
$mobilePattern = "/^[6-9]\d{9}$/";
var_dump(preg_match($mobilePattern, "9876543210")); // 1

// Indian PIN code — 6 digits, 1-9 से शुरू
$pinPattern = "/^[1-9]\d{5}$/";
var_dump(preg_match($pinPattern, "110001")); // 1

// URL
$urlPattern = "/^https?:\/\/[a-z0-9]+([\-\.]{1}[a-z0-9]+)*\.[a-z]{2,}(\/.*)?$/i";
var_dump(preg_match($urlPattern, "https://hindinotespoint.in")); // 1

// Password — 8+, uppercase, lowercase, digit
$passPattern = "/^(?=.*[a-z])(?=.*[A-Z])(?=.*\d).{8,}$/";
var_dump(preg_match($passPattern, "MyPass123")); // 1
var_dump(preg_match($passPattern, "weakpass")); // 0

// GST Number — 15 chars: 2digit state + 10 PAN + 1Z + 2alphanumeric
$gstPattern = "/^\d{2}[A-Z]{5}\d{4}[A-Z]{1}[A-Z\d]{1}Z[A-Z\d]{1}$/";
var_dump(preg_match($gstPattern, "29ABCDE1234F1ZS")); // 1

// Aadhaar — 12 digits (not starting with 0 or 1)
$aadhaarPattern = "/^[2-9]\d{11}$/";
var_dump(preg_match($aadhaarPattern, "234567891234")); // 1

// Slug — URL-safe lowercase
$slugPattern = "/^[a-z0-9]+(?:-[a-z0-9]+)*$/";
var_dump(preg_match($slugPattern, "php-tutorial-hindi")); // 1

// Slug बनाना from title
function makeSlug(string $title): string {
  $slug = strtolower(trim($title));
  $slug = preg_replace("/[^a-z0-9\s-]/", "", $slug); // Non-alphanumeric remove
  $slug = preg_replace("/\s+/", "-", $slug); // Spaces → dash
  return preg_replace("/--+/", "-", $slug); // Multiple dashes → one
}
echo makeSlug("PHP Tutorial for Beginners!");
// php-tutorial-for-beginners
?>

<?php
// User input को pattern में safe use करना
$search = "C++ (language)"; // Special chars!
$escaped = preg_quote($search, "/"); // C\+\+ \(language\)
$pattern = "/" . $escaped . "/i";
preg_match($pattern, "I love C++ (language)"); // ✅ safe
?>