Getting Started with PHP Functions_PHP Tutorial-PHP Tutorial-php.cn

Getting Started with PHP Functions_PHP Tutorial

WBOY

Release： 2016-07-15 13:24:53

Original

914 people have browsed it

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>

Copy after login

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.";?＞

Copy after login

Output of the above code:

Hello world!My name is David Yang.That's right, David Yang is my name.

Copy after login

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");?＞

Copy after login

Output of the above code:

My name is David Yang.My name is Mike Yang.My name is John Yang.

Copy after login

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","...");?＞

Copy after login

Output of the above code:

My name is David Yang.My name is Mike Yang!My name is John Yang...

Copy after login

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);？＞

Copy after login

Output of the above code:

1 + 16 = 17

Copy after login