Home > Article > Backend Development > Getting Started with PHP Functions_PHP Tutorial
Getting Started with PHP Functions_PHP Tutorial
- WBOYOriginal
- 2016-07-15 13:24:53862browse
The real power of PHP comes from its functions.
In PHP, more than 700 built-in functions are provided.
PHP Functions
In this tutorial, we will show you how to create your own functions.
Creating PHP Functions
A function is a block of code that can be executed whenever needed.
Creating PHP functions :
All functions start with the keyword "function()"
Name the function - the name of the function should prompt out its functionality. Function names start with a letter or underscore.
Add "{" - The part after the opening curly brace is the code of the function.
Insert function code
Add a "}" - the function ends with a closing curly brace.
Example
A simple function that prints my name when called:
<html><body><?phpfunction writeMyName() { echo "David Yang"; }writeMyName();?></body></html> |
Using PHP Function
Now, we are going to use this function in a PHP script:
＜?phpfunction writeMyName() { echo "David Yang"; }echo "Hello world!<br>";echo "My name is ";writeMyName();echo ".<br>That's right, ";writeMyName();echo " is my name.";?＞ |
Output of the above code:
Hello world!My name is David Yang.That's right, David Yang is my name. |
PHP Functions - Adding Parameters
Our first function is a very simple function. It can only output a static string.
We add more functionality to functions by being able to add parameters. A parameter is like a variable.
You may notice that there is a bracket after the function name, such as writeMyName(). Parameters are specified in parentheses.
Example 1
The following example outputs different names, but the last name is the same:
＜?phpfunction writeMyName($fname) { echo $fname . " Yang.<br>"; }echo "My name is ";writeMyName("David");echo "My name is ";writeMyName("Mike");echo "My name is ";writeMyName("John");?＞ |
Output of the above code:
My name is David Yang.My name is Mike Yang.My name is John Yang. |
Example 2
The following function has two parameters:
＜?phpfunction writeMyName($fname,$punctuation) { echo $fname . " Yang" . $punctuation . "<br>"; }echo "My name is ";writeMyName("David",".");echo "My name is ";writeMyName("Mike","!");echo "My name is ";writeMyName("John","...");?＞ |
Output of the above code:
My name is David Yang.My name is Mike Yang!My name is John Yang... |
PHP Function - Return Value
functions can also be used to return values.
Example
＜?phpfunction add($x,$y) { $total = $x + $y; return $total; }echo "1 + 16 = " . add(1,16);？＞ |
Output of the above code:
1 + 16 = 17 |