Commonly used php built-in functions list with examples

PHP is a widely used server-side scripting language that is especially popular for creating dynamic web pages and web applications. One of the reasons for its popularity is its vast collection of built-in functions that can help with a wide range of tasks. In this article, we’ll explore some of the commonly used PHP built-in functions, organized into different types, with examples.

Commonly Used PHP Built-in Functions Types List with Popular Functions and Examples:

String Functions:

strlen() – Returns the length of a string
substr() – Returns a portion of a string
str_replace() – Replaces all occurrences of a search string with a replacement string
strtolower() – Converts a string to lowercase
strtoupper() – Converts a string to uppercase

Example:

$text = "Hello World!";echo strlen($text); // Output: 12echo substr($text, 0, 5); // Output: Helloecho str_replace("World", "Universe", $text); // Output: Hello Universe!echo strtolower($text); // Output: hello world!echo strtoupper($text); // Output: HELLO WORLD!

Array Functions:

count() – Returns the number of elements in an array
array_push() – Adds one or more elements to the end of an array
array_pop() – Removes the last element from an array
array_merge() – Merges two or more arrays into a single array
array_search() – Searches an array for a given value and returns the corresponding key if successful

Example:

$fruits = array("apple", "banana", "cherry");echo count($fruits); // Output: 3array_push($fruits, "orange");print_r($fruits); // Output: Array ( [0] => apple [1] => banana [2] => cherry [3] => orange )echo array_pop($fruits); // Output: orangeprint_r($fruits); // Output: Array ( [0] => apple [1] => banana [2] => cherry )$colors1 = array("red", "green");$colors2 = array("blue", "yellow");print_r(array_merge($colors1, $colors2)); // Output: Array ( [0] => red [1] => green [2] => blue [3] => yellow )print_r(array_slice($fruits, 0, 2)); // Output: Array ( [0] => apple [1] => banana )

Date and Time Functions:

time() – Returns the current Unix timestamp
date() – Formats a local time/date
strtotime() – Parses an English textual datetime description into a Unix timestamp
gmdate() – Formats a GMT/UTC date/time
strftime() – Formats a date/time according to local conventions

Example:

echo date("Y-m-d"); // Output: 2023-03-01echo time(); // Output: Current Unix timestampecho strtotime("next Friday"); // Output: Unix timestamp for next Fridayecho mktime(0, 0, 0, 1, 1, 2023); // Output: Unix timestamp for January 1, 2023echo strftime

File System Functions:

file_get_contents() – Reads entire file into a string
file_put_contents() – Write a string to a file
is_file() – Returns true if the file exists and is a regular file
is_dir() – Returns true if the file exists and is a directory
unlink() – Deletes a file

Example:

$text = file_get_contents("file.txt");echo $text; // Output: Contents of file.txtfile_put_contents("newfile.txt", "This is some text");echo is_file("file.txt"); // Output: trueecho is_dir("mydir"); // Output: trueunlink("file.txt"); // Deletes file.txt

Database Functions:

mysqli_connect() – Opens a new connection to the MySQL server
mysqli_query() – Performs a query on the database
mysqli_fetch_array() – Fetches a result row as an associative array, a numeric array, or both
mysqli_num_rows() – Returns the number of rows in a result set
mysqli_close() – Closes a previously opened database connection

Example:

// Establish connection to MySQL server$conn = mysqli_connect("localhost", "username", "password", "database_name");// Perform a query on the database$result = mysqli_query($conn, "SELECT * FROM users");// Fetch result rows as an associative arraywhile ($row = mysqli_fetch_array($result, MYSQLI_ASSOC)) {    echo "Name: " . $row["name"] . " Email: " . $row["email"];}// Get number of rows in the result setecho "Total rows: " . mysqli_num_rows($result);// Close database connectionmysqli_close($conn);

Math Functions:

pow() – Returns the value of a number raised to a power
round() – Rounds a floating-point number to a specified number of decimal places
max() – Returns the highest value in an array
min() – Returns the lowest value in an array
rand() – Generates a random integer

Example:

echo rand(1, 10); // Output: Random number between 1 and 10echo abs(-5); // Output: 5echo floor(2.8); // Output: 2echo ceil(2.1); // Output: 3echo sqrt(16); // Output: 4

Other Functions:

isset() – Determines if a variable is set and is not null
empty() – Determines if a variable is empty
print_r() – Prints human-readable information about a variable
var_dump() – Dumps information about a variable
die() – Prints a message and terminates the current script

Example:

$var1 = "hello";$var2 = "";if (isset($var1)) {    echo "Variable var1 is set";}if (empty($var2)) {    echo "Variable var2 is empty";}$fruits = array("apple", "banana", "cherry");print_r($fruits); // Output: Array ( [0] => apple [1] => banana [2] => cherry )var_dump($fruits); // Output: array(3) { [0]=> string(5) "apple" [1]=> string(6) "banana" [2]=> string(6) "cherry" }echo "Script terminated";die(); // Terminates the script

Conclusion:

In conclusion, PHP has a vast collection of built-in functions that can help with a wide range of tasks. In this article, we’ve explored some of the commonly used PHP built-in functions, organized into different types, with examples. Whether you’re working with strings and arrays, handling dates and times, working with files and directories, connecting to databases, performing math operations, or working with variables, there’s a PHP built-in function that can help. The best way to learn more about PHP built-in functions is to explore the PHP documentation and try out different functions in your own code.

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