PHP Functions: A Beginner’s Guide | PHP Beginner to Advance

Functions are an essential part of any programming language, and PHP is no exception. In this blog post, we’ll be taking a look at how to create and use functions in PHP, including built-in functions and user-defined functions.

Built-in Functions in PHP

PHP comes with a variety of built-in functions that can be used to perform common tasks, such as string manipulation, mathematical operations, and array manipulation. Some examples of built-in functions in PHP include:

  • strlen(): Returns the length of a string
  • round(): Rounds a number to a specified number of decimal places
  • count(): Counts the number of elements in an array

Here’s an example of how to use the built-in strlen() function to find the length of a string:

$name = "John Doe";
$length = strlen($name);
echo "The length of the string is: " . $length;

User-Defined Functions in PHP

In addition to built-in functions, you can also create your own functions in PHP. User-defined functions allow you to organize your code and reuse it throughout your program. Here’s an example of how to create a simple user-defined function that adds two numbers together:

function add($a, $b) {
  return $a + $b;

$result = add(3, 5);
echo "The result is: " . $result;

In this example, we’ve created a function called add() that takes in two parameters, $a and $b. Inside the function, we use the return statement to return the sum of $a and $b.

Functions in PHP can also accept an optional parameter with a default value, which can be used if no value is passed to the function. Here’s an example of how to create a user-defined function that calculates the area of a rectangle with a default value for width.

function rectangle_area($height, $width = 5) {
  return $height * $width;

$area = rectangle_area(10);
echo "The area is: " . $area;

In this example, width parameter has a default value of 5, if no width value is passed to the function, it will use the default value.

In Conclusion

Functions are an essential part of programming and are a great way to organize your code and make it more reusable. Whether you’re using built-in functions or creating your own, understanding how to use functions in PHP is an important part of becoming a proficient PHP developer.

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