Introduction to the usage of php custom functions_PHP tutorial

This article introduces the usage of PHP custom functions in detail, including 1. The function name cannot have the same name as an existing function name. 2. Function names can only contain letters, numbers and underscores. 3. The function name cannot start with a number

Custom function

7.2.1 Basic principles of function naming:

1. The function name cannot have the same name as an existing function name.

2. Function names can only contain letters, numbers and underscores.

3. The function name cannot start with a number

7.2.2 Basic usage: declare with function

The code is as follows

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代码如下	复制代码
//创建函数　 function funcCountArea($radius) { return $radius*$radius*pi(); } //使用函数 $area = funcCountArea(20); echo $area; echo ' ';   $area2 = funcCountArea(30); echo $area2; ?>   output 1256.63706144 2827.43338823

//Create function　

代码如下	复制代码
$a = 5; function funcChange($a) { $a = 2 * $a; } funcChange ($a); echo $a; ?>   output 5

function funcCountArea($radius)

{

代码如下	复制代码
$a = 5; function funcChange(&$a) { $a = 2 * $a; } funcChange ($a); echo $a; ?>   output 10

return $radius*$radius*pi();

}

代码如下	复制代码
function funcUserInfo($username,$password) { $userInfo = array($username,$password); return $userInfo; } $arr = funcUserInfo('anllin','123456'); print_r($arr); ?>   output Array ( [0] => anllin [1] => 123456 )

//Use function $area = funcCountArea(20); echo $area; echo '
'; $area2 = funcCountArea(30); echo $area2; ?>
output 1256.63706144
2827.43338823
7.2.3 Passing parameters by value

The code is as follows	Copy code
<🎜>$a = 5;<🎜> <🎜>function funcChange($a)<🎜> <🎜>{<🎜> <🎜> $a = 2 * $a;<🎜> <🎜>}<🎜> <🎜>funcChange ($a);<🎜> <🎜>echo $a;<🎜> <🎜>?> output 5

7.2.4 Passing parameters by reference

The code is as follows	Copy code
<🎜>$a = 5;<🎜> <🎜>function funcChange(&$a)<🎜> <🎜>{<🎜> <🎜> $a = 2 * $a;<🎜> <🎜>}<🎜> <🎜>funcChange ($a);<🎜> <🎜>echo $a;<🎜> <🎜>?> output 10

7.2.5 Function calls that return multiple values

The code is as follows	Copy code
<🎜>function funcUserInfo($username,$password)<🎜> <🎜>{<🎜> <🎜> $userInfo = array($username,$password);<🎜> <🎜> return $userInfo;<🎜> <🎜>}<🎜> <🎜> <🎜> <🎜>$arr = funcUserInfo('anllin','123456');<🎜> <🎜> <🎜> <🎜>print_r($arr);<🎜> <🎜>?> output Array ( [0] => anllin [1] => 123456 )

7.2.6 Another function call that returns multiple values ​​(practical: recommended)

function funcUserInfo($username, $password)

The code is as follows

代码如下

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function funcUserInfo($username, $password) { $userInfo [] = $username; $userInfo [] = $password; return $userInfo; } $arr[] = funcUserInfo ( 'Bob', '512655' ); $arr[] = funcUserInfo ( 'John', '458736' ); $arr[] = funcUserInfo ( 'Mark', '925472' ); print_r ( $arr ); ?>   output Array ( [0] => Array ( [0] => Bob [1] => 512655 ) [1] => Array ( [0] => John [1] => 458736 ) [2] => Array ( [0] => Mark [1] => 925472 ) )

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{

$userInfo [] = $username;

$userInfo [] = $password; return $userInfo; } $arr[] = funcUserInfo ( 'Bob', '512655' ); $arr[] = funcUserInfo ( 'John', '458736' );

$arr[] = funcUserInfo ( 'Mark', '925472' );

print_r ( $arr );

?> output Array ( [0] => Array ( [0] => Bob [1] => 512655 ) [1] => Array ( [0] => John [1] => 458736 ) [2] => Array ( [0] => Mark [1] => 925472 ) ) Note: Function calls are not case-sensitive, but variable names are case-sensitive. http://www.bkjia.com/PHPjc/629233.htmlwww.bkjia.comtruehttp: //www.bkjia.com/PHPjc/629233.htmlTechArticleThis article introduces the usage of PHP custom functions in detail, including 1. The function name cannot be the same as the existing function name Duplicate name. 2. Function names can only contain letters, numbers and underscores. 3. The function name cannot start with a number...