PHP Functions

PHP is a popular programming language used for web development. It offers a wide range of built-in functions that can be used to perform various tasks. Here are some commonly used PHP functions categorized by their functionality:

1. String Functions:

• strlen($string): Returns the length of a string.
• str_replace($search, $replace, $string): Replaces all occurrences of a substring with another substring in a string.
• strtolower($string): Converts a string to lowercase.
• strtoupper($string): Converts a string to uppercase.
• substr($string, $start, $length): Returns a substring from a string.
• trim($string): Removes whitespace or other specified characters from the beginning and end of a string.

2. Array Functions:

• count($array): Returns the number of elements in an array.
• array_push($array, $element1, $element2, ...): Adds one or more elements to the end of an array.
• array_pop($array): Removes and returns the last element of an array.
• array_merge($array1, $array2): Merges two or more arrays into a single array.
• array_search($value, $array): Searches an array for a given value and returns the corresponding key if found.

3. File System Functions:

• file_get_contents($filename): Reads the contents of a file into a string.
• file_put_contents($filename, $data): Writes a string to a file.
• file_exists($filename): Checks if a file or directory exists.
• is_file($filename): Checks if a given filename is a regular file.
• unlink($filename): Deletes a file.

4. Database Functions (using MySQLi extension):

• mysqli_connect($host, $username, $password, $database): Opens a connection to a MySQL database.
• mysqli_query($connection, $query): Executes a query on the database.
• mysqli_fetch_assoc($result): Fetches a row from a result set as an associative array.
• mysqli_insert_id($connection): Returns the auto-generated ID used in the last query.
• mysqli_close($connection): Closes the database connection.

These are just a few examples of the many functions available in PHP. You can refer to the official PHP documentation for a comprehensive list and detailed explanations of all the functions: https://www.php.net/manual/en/funcref.php