The real power of PHP comes from its functions.
In PHP - there are more than 700 built-in functions available.
--------------------------------------------------------------------------------
[color=940306]PHP Functions[/color]
In this tutorial we will show you how to create your own functions. -------------------------------------------------------------------------------- [color=940306]Create a PHP Function[/color]
A function is a block of code that can be executed whenever we need it. Creating PHP functions: - All functions start with the word "function()"
- 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)
- Add a "{" - The function code starts after the opening curly brace
- Insert the function code
- Add a "}" - The function is finished by a closing curly brace [color=940306]Example[/color]
A simple function that writes my name when it is called:
Now we will use the function in a PHP script:
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. [color=FA0309]Example 1[/color]
The following example will write different first names, but the same last name:
The following function has two parameters:
-------------------------------------------------------------------------------- PHP Functions - Return values
Functions can also be used to return values. [color=FA0309]Example[/color]
In this tutorial we will show you how to create your own functions. -------------------------------------------------------------------------------- [color=940306]Create a PHP Function[/color]
A function is a block of code that can be executed whenever we need it. Creating PHP functions: - All functions start with the word "function()"
- 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)
- Add a "{" - The function code starts after the opening curly brace
- Insert the function code
- Add a "}" - The function is finished by a closing curly brace [color=940306]Example[/color]
A simple function that writes my name when it is called:
<html>
<body>
<?php
function writeMyName()
{
echo "Kai Jim Refsnes";
}writeMyName();
?>
</body>
</html>
--------------------------------------------------------------------------------
[color=940306]Use a PHP Function[/color]<body>
<?php
function writeMyName()
{
echo "Kai Jim Refsnes";
}writeMyName();
?>
</body>
</html>
Now we will use the function in a PHP script:
<html>
<body>
<?php
function writeMyName()
{
echo "Kai Jim Refsnes";
}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:
<body>
<?php
function writeMyName()
{
echo "Kai Jim Refsnes";
}echo "Hello world!<br />";
echo "My name is ";
writeMyName();
echo ".<br />That's right, ";
writeMyName();
echo " is my name.";
?>
</body>
</html>
Hello world!
My name is Kai Jim Refsnes.
That's right, Kai Jim Refsnes is my name.
--------------------------------------------------------------------------------
[color=940306]PHP Functions - Adding parameters[/color]My name is Kai Jim Refsnes.
That's right, Kai Jim Refsnes is my name.
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. [color=FA0309]Example 1[/color]
The following example will write different first names, but the same last name:
<html>
<body>
<?php
function writeMyName($fname)
{
echo $fname . " Refsnes.<br />";
}echo "My name is ";
writeMyName("Kai Jim");echo "My name is ";
writeMyName("Hege");echo "My name is ";
writeMyName("Stale");
?>
</body>
</html>
The output of the code above will be:
<body>
<?php
function writeMyName($fname)
{
echo $fname . " Refsnes.<br />";
}echo "My name is ";
writeMyName("Kai Jim");echo "My name is ";
writeMyName("Hege");echo "My name is ";
writeMyName("Stale");
?>
</body>
</html>
My name is Kai Jim Refsnes.
My name is Hege Refsnes.
My name is Stale Refsnes.
[color=FA0309]Example 2[/color]My name is Hege Refsnes.
My name is Stale Refsnes.
The following function has two parameters:
<html>
<body>
<?php
function writeMyName($fname,$punctuation)
{
echo $fname . " Refsnes" . $punctuation . "<br />";
}echo "My name is ";
writeMyName("Kai Jim",".");echo "My name is ";
writeMyName("Hege","!");echo "My name is ";
writeMyName("Ståle","...");
?>
</body>
</html>
The output of the code above will be:
<body>
<?php
function writeMyName($fname,$punctuation)
{
echo $fname . " Refsnes" . $punctuation . "<br />";
}echo "My name is ";
writeMyName("Kai Jim",".");echo "My name is ";
writeMyName("Hege","!");echo "My name is ";
writeMyName("Ståle","...");
?>
</body>
</html>
My name is Kai Jim Refsnes.
My name is Hege Refsnes!
My name is Ståle Refsnes...
My name is Hege Refsnes!
My name is Ståle Refsnes...
-------------------------------------------------------------------------------- PHP Functions - Return values
Functions can also be used to return values. [color=FA0309]Example[/color]
<html>
<body>
<?php
function add($x,$y)
{
$total = $x + $y;
return $total;
}echo "1 + 16 = " . add(1,16)
?>
</body>
</html>
The output of the code above will be:
<body>
<?php
function add($x,$y)
{
$total = $x + $y;
return $total;
}echo "1 + 16 = " . add(1,16)
?>
</body>
</html>
1 + 16 = 17