PHP Functions

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The real power of PHP comes from its functions.

In PHP, there are more than 700 built-in functions.

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PHP Built-in Functions

For a complete reference and examples of the built-in functions, please visit our PHP Reference.

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PHP Functions

In this chapter we will show you how to create your own functions.

To keep the script from being executed when the page loads, you can put it into a function.

A function will be executed by a call to the function.

You may call a function from anywhere within a page.

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Create a PHP Function

A function will be executed by a call to the function.

Syntax

function functionName()
{
code to be executed;
}

PHP function guidelines:

• Give the function a name that reflects what the function does
• The function name can start with a letter or underscore (not a number)

Example

A simple function that writes my name when it is called:

PHP Code

function writeName()
{
echo "SamGenius";
}

echo "My name is ";
writeName();


output


My name is Samgenius

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PHP Functions - Adding parameters

To add more functionality to a function, we can add parameters. A parameter is just like a variable.

Parameters are specified after the function name, inside the parentheses.

Example 1

The following example will write different first names, but equal last name:

PHP Code

function writeName($fname)
{
echo $fname . " Refsnes.<br />";
}

echo "My name is ";
writeName("Kai Jim");
echo "My sister name is ";
writeName("Hege");
echo "My brother name is ";
writeName("Stale");


output


My name is Kai Jim Refsnes.
My sister name is Hege Refsnes.
My brother name is Stale Refsnes.

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PHP Functions - Return values

To let a function return a value, use the return statement.

Example

<?php

 function add($x,$y)

 {

  $total=$x+$y;

  return $total;

 }

 echo "1 + 16 = " . add(1,16);

?>