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:
- 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.
- 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, $array): Searches an array for a given value and returns the corresponding key if found.
- File System Functions:
file_get_contents($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.
- 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