PHP Functions
In this lesson we will show you how to create your own functions.For a situation and examples of the built-in functions, please visit our PHP Reference.
Create a PHP Function
A function is a block of code that can be executed whenever we need it.
(1) All functions start with the word “function()”
(2) Name the function – It should be possible to understand what the function does by its name. The name can start with a letter or underscore (not a number)
(3) Add a “{” – The function code starts after the opening curly brace
(4) Insert the function code
(5) Add a “}” – The function is finished by a closing curly brace
Example
A simple function that writes my name when it is called:
<html><body>
<?php
function writeMyName()
{
echo “chintan”;
}
writeMyName();
?>
</body></html>
Use a PHP Function
Now we will use the function in a PHP script:
<html><body>
<?php
function writeMyName()
{
echo “chintan”;
}
echo “Hello world!<br />”;
echo “My name is “;
writeMyName();
echo “.<br />That’s right, “;
writeMyName();
echo ” is my name.”;
?>
</body>
</html>
The output of the code above will be:
Hello world!
My name is chintan.
That’s right, chintan is my name.
PHP Functions – Adding parameters
Our first function (writeMyName()) is a very simple function. It only writes a static string.
To add more functionality to a function, we can add parameters. A parameter is just like a variable.
You may have noticed the parentheses after the function name, like: writeMyName(). The parameters are specified inside the parentheses.
Example 1
The following example will write different first names, but the same last name:
<html><body>
<?php
function writeMyName($fname)
{
echo $fname . ” Refsnes.<br />”;
}
echo “My name is “;
writeMyName(“chintan”);
echo “My name is “;
writeMyName(“Den”);
echo “My name is “;
writeMyName(“James”);
?>
</body></html>
The output of the code above will be:
My name is chintan Refsnes.
My name is Den Refsnes.
My name is James Refsnes.
Example 2
The following function has two parameters:
<html><body>
<?php
function writeMyName($fname,$punctuation)
{
echo $fname . ” Refsnes” . $punctuation . “<br />”;
}
echo “My name is “;
writeMyName(“chintan”,”.”);
echo “My name is “;
writeMyName(“Den”,”!”);
echo “My name is “;
writeMyName(“James”,”…”);
?>
</body>
</html>
The output of the code above will be:
My name is chintan Refsnes.
My name is Den Refsnes!
My name is James Refsnes…
PHP Functions – Return values
Functions can also be used to return values.
Example
<html><body>
<?php
function add($x,$y)
{
$total = $x + $y;
return $total;
}
echo “1 + 10 = ” . add(1,10);
?>
</body></html>
The output of the code above will be:
1 + 10= 11
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