7.1.标准函数
标准php发行包中有1000多个标准函数,这些标准函数都是系统内置的,不需要用户创建就可以直接使用
如:
复制代码 代码如下:
echo md5('123456');
echo '
';
echo sha1('123456');
echo '
';
echo pi();
?>
output
e10adc3949ba59abbe56e057f20f883e
7c4a8d09ca3762af61e59520943dc26494f8941b
3.14159265359
7.2.自定义函数
7.2.1函数命名基本原则:
1.函数名不能和已有的函数名重名。
2.函数名只能包含字母、数字和下划线。
3.函数名不能以数字开头
7.2.2基本使用:用function进行声明
复制代码 代码如下:
//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
7.2.3按值传参
复制代码 代码如下:
$a = 5;
function funcChange($a)
{
$a = 2 * $a;
}
funcChange ($a);
echo $a;
?>
output
5
7.2.4按引用传参
复制代码 代码如下:
$a = 5;
function funcChange(&$a)
{
$a = 2 * $a;
}
funcChange ($a);
echo $a;
?>
output
10
7.2.5返回多个值的函数调用
复制代码 代码如下:
function funcUserInfo($username,$password)
{
$userInfo = array($username,$password);
return $userInfo;
}
$arr = funcUserInfo('anllin','123456');
print_r($arr);
?>
output
Array ( [0] => anllin [1] => 123456 )
7.2.6另一种返回多个值的函数调用(实用:推荐)
复制代码 代码如下:
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 ) )
注意:函数调用是不区分大小写的,但是变量名是区分大小写的。
7.2.7理解作用域:
局部变量:
在函数内部声明的变量。
全局变量:
在函数外部声明的变量。
7.2.8局部变量转换成全局变量
复制代码 代码如下:
$a = 5;
function funcChangeValue()
{
global $a;
$a = 10;
}
funcChangeValue();
echo $a;
?>
output
10
7.2.9超级全局变量$GLOBALR的使用
复制代码 代码如下:
$GLOBALS['a'] = 5;
function funcChangeValue()
{
$GLOBALS['a'] = 10;
}
funcChangeValue();
echo $GLOBALS['a'];
?>
Output
10
7.3.文件包含
7.3.1 Include的使用,可以包含相同的文件多次
复制代码 代码如下:
include 'demo1.php';
include 'demo1.php';
include 'demo1.php';
?>
output
e10adc3949ba59abbe56e057f20f883e
7c4a8d09ca3762af61e59520943dc26494f8941b
3.14159265359
--------------------------------------------------------------------------------
e10adc3949ba59abbe56e057f20f883e
7c4a8d09ca3762af61e59520943dc26494f8941b
3.14159265359
--------------------------------------------------------------------------------
e10adc3949ba59abbe56e057f20f883e
7c4a8d09ca3762af61e59520943dc26494f8941b
3.14159265359
7.3.2 include_once使用上和include没什么区别,但是调用多次只会包含相同的文件一次
复制代码 代码如下:
include_once 'demo1.php';
include_once 'demo1.php';
include_once 'demo1.php';
?>
output
e10adc3949ba59abbe56e057f20f883e
7c4a8d09ca3762af61e59520943dc26494f8941b
3.14159265359
7.3.3 require() 语句包含并运行指定文件。
复制代码 代码如下:
require 'demo1.php';
require 'demo1.php';
require 'demo1.php';
?>
output
e10adc3949ba59abbe56e057f20f883e
7c4a8d09ca3762af61e59520943dc26494f8941b
3.14159265359
--------------------------------------------------------------------------------
e10adc3949ba59abbe56e057f20f883e
7c4a8d09ca3762af61e59520943dc26494f8941b
3.14159265359
--------------------------------------------------------------------------------
e10adc3949ba59abbe56e057f20f883e
7c4a8d09ca3762af61e59520943dc26494f8941b
3.14159265359
7.3.4 require_once() 语句在脚本执行期间包含并运行指定文件.但是不重复包含相同的文件。
复制代码 代码如下:
require_once 'demo1.php';
require_once 'demo1.php';
require_once 'demo1.php';
?>
output
e10adc3949ba59abbe56e057f20f883e
7c4a8d09ca3762af61e59520943dc26494f8941b
3.14159265359s
7.3.5 include与require的区别
Include后面如果还有其他代码,当调用include出错时,后面的代码还会继续执行,但是require则不会。
Include在调用一个不存在的文件时,会给出警告,但是会继续执行后面的代码。
复制代码 代码如下:
include 'demo111.php';
echo('this is demo13.php');
?>
output
Warning: include(demo111.php) [function.include]: failed to open stream: No such file or directory in D:\AppServ\www\Basic7\demo13.php on line 2
Warning: include() [function.include]: Failed opening 'demo111.php' for inclusion (include_path='.;C:\php5\pear') in D:\AppServ\www\Basic7\demo13.php on line 2
this is demo13.php
Require在调用一个不存在的文件时,会给出一个错误,并中止代码的执行。
复制代码 代码如下:
require 'demo111.php';
echo('this is demo14.php');
?>
Output
Warning: require(demo111.php) [function.require]: failed to open stream: No such file or directory in D:\AppServ\www\Basic7\demo14.php on line 2
Fatal error: require() [function.require]: Failed opening required 'demo111.php' (include_path='.;C:\php5\pear') in D:\AppServ\www\Basic7\demo14.php on line 2
7.4.魔法常量
名称 |
描述 |
_FILE_ |
当前文件名 |
_LINE_ |
当前行号 |
_FUNCTION_ |
当前函数名 |
_CLASS_ |
当前类名 |
_METHOD_ |
当前方法名 |
复制代码 代码如下:
echo __FILE__;
echo '
';
echo __LINE__;
echo '
';
function funcTest()
{
echo __FUNCTION__;
}
funcTest();
?>
output
D:\AppServ\www\Basic7\demo15.php
5
funcTest

What’s still popular is the ease of use, flexibility and a strong ecosystem. 1) Ease of use and simple syntax make it the first choice for beginners. 2) Closely integrated with web development, excellent interaction with HTTP requests and database. 3) The huge ecosystem provides a wealth of tools and libraries. 4) Active community and open source nature adapts them to new needs and technology trends.

PHP and Python are both high-level programming languages that are widely used in web development, data processing and automation tasks. 1.PHP is often used to build dynamic websites and content management systems, while Python is often used to build web frameworks and data science. 2.PHP uses echo to output content, Python uses print. 3. Both support object-oriented programming, but the syntax and keywords are different. 4. PHP supports weak type conversion, while Python is more stringent. 5. PHP performance optimization includes using OPcache and asynchronous programming, while Python uses cProfile and asynchronous programming.

PHP is mainly procedural programming, but also supports object-oriented programming (OOP); Python supports a variety of paradigms, including OOP, functional and procedural programming. PHP is suitable for web development, and Python is suitable for a variety of applications such as data analysis and machine learning.

PHP originated in 1994 and was developed by RasmusLerdorf. It was originally used to track website visitors and gradually evolved into a server-side scripting language and was widely used in web development. Python was developed by Guidovan Rossum in the late 1980s and was first released in 1991. It emphasizes code readability and simplicity, and is suitable for scientific computing, data analysis and other fields.

PHP is suitable for web development and rapid prototyping, and Python is suitable for data science and machine learning. 1.PHP is used for dynamic web development, with simple syntax and suitable for rapid development. 2. Python has concise syntax, is suitable for multiple fields, and has a strong library ecosystem.

PHP remains important in the modernization process because it supports a large number of websites and applications and adapts to development needs through frameworks. 1.PHP7 improves performance and introduces new features. 2. Modern frameworks such as Laravel, Symfony and CodeIgniter simplify development and improve code quality. 3. Performance optimization and best practices further improve application efficiency.

PHPhassignificantlyimpactedwebdevelopmentandextendsbeyondit.1)ItpowersmajorplatformslikeWordPressandexcelsindatabaseinteractions.2)PHP'sadaptabilityallowsittoscaleforlargeapplicationsusingframeworkslikeLaravel.3)Beyondweb,PHPisusedincommand-linescrip

PHP type prompts to improve code quality and readability. 1) Scalar type tips: Since PHP7.0, basic data types are allowed to be specified in function parameters, such as int, float, etc. 2) Return type prompt: Ensure the consistency of the function return value type. 3) Union type prompt: Since PHP8.0, multiple types are allowed to be specified in function parameters or return values. 4) Nullable type prompt: Allows to include null values and handle functions that may return null values.


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