W3school's PHP tutorial refining (2) PHP advanced_PHP tutorial
1 Date()
1.1 Date()函数
语法:date(format,timestamp)
format:必需。规定时间戳的格式。
timestamp:可选。规定时间戳。默认是当前的日期和时间。
1.2 时间戳(Timestamp)
自1970.1.1(00:00:00GMT)以来的秒数
1.3 格式化日期
date()函数的format参数规定了如何格式化日期/时间
d:月中的天(01-31)
m:当前的月,以数字计(01-12)
Y:当前的年(四位数)
";echo date("Y-m-d");?>1.4 添加时间戳
date()函数的timestamp参数规定了一个时间戳
1.5 mktime()函数
mktime()函数可为指定的日期返回Unix时间戳
语法:mktime(hour,minute,second,month,day,year,is_dst)
2 引用文件
2.1 include()函数
2.2 require()函数
和include()的错误处理方式不同:include()函数会生成一个警告(但是脚本会继续执行),而require()函数会生成一个致命错误(fatal error)(在错误发生后脚本会停止执行)
3 文件处理
3.1 打开文件 fopen()函数
第一个参数含有要打开的文件的名称
第二个参数规定了使用哪种模式来打开文件
模式
描述
r
只读。在文件的开头开始。
r+
读/写。在文件的开头开始。
w
只写。打开并清空文件的内容;如果文件不存在则创建新文件
w+
读/写。打开并清空文件的内容;如果文件不存在则创建新文件
a
追加。打开并向文件末端进行写操作,如果文件不存在则创建新文件
a+
读/追加。通过向文件末端写内容,来保持文件内容
x
只写。创建新文件。如果文件已存在则返回false
x+
读/写。创建新文件。如果文件已存在,则返回false和一个错误。如果fopen()无法打开指定文件,则返回0(false)
3.2 关闭文件 fclose()函数
3.3 检测End-of-file feof()函数
3.4 逐行读取文件 fgets()函数
在调用该函数之后,文件指针会移动到下一行
";}fclose($file);?>3.5 逐字符读取文件 fgetc()函数
在调用该函数之后,文件指针会移动到下一个字符
4 文件上传
4.1 创建表单
4.2 上传脚本 全局数组$_FILES
0){echo "Error: " . $_FILES["file"]["error"] . "
";}else{echo "Upload: " . $_FILES["file"]["name"] . "
";echo "Type: " . $_FILES["file"]["type"] . "
";echo "Size: " . ($_FILES["file"]["size"] / 1024) . " Kb
";echo "Stored in: " . $_FILES["file"]["tmp_name"];}?>$_FILES数组的第一个参数是表单的input name,第二个下标可以是:
name:被上传文件的名称
type:被上传文件的类型
size:被上传文件的大小
tmp_name:存储在服务器的文件的临时副本的名称
error:由文件上传导致的错误代码
4.3 上传限制
限制上传.gif或者.jpeg文件,文件大小必须小于20kb:
0){echo "Error: " . $_FILES["file"]["error"] . "
";}else{echo "Upload: " . $_FILES["file"]["name"] . "
";echo "Type: " . $_FILES["file"]["type"] . "
";echo "Size: " . ($_FILES["file"]["size"] /1024) . " Kb
";echo "Stored in: " . $_FILES["file"]["tmp_name"];}else{echo "Invalid file";}}?>
4.4 保存被上传的文件
Copy the temporary copy of the uploaded file created in the temporary folder in the above example to another location to prevent it from disappearing at the end of the script
0){echo "Error: " . $_FILES["file"]["error"] . "
";}else{echo "Upload: " . $_FILES["file"]["name"] . "
";echo "Type: " . $_FILES["file"]["type" ] . "
";echo "Size: " . ($_FILES["file"]["size"] /1024) . " Kb
";echo "Temp file: " . $_FILES["file"]["tmp_name"] . "
";if(file_exists("upload/" . $_FILES["file"]["name"])){echo $_FILES[ "file"]["name"] . "already exists. ";}else{move_uploaded_file($_FILES["file"]["tmp_name"], "upload/" . $_FILES["file"]["name" ]);echo "Stored in: " . "upload/" . $_FILES["file"]["name"];}}}else{echo "Invalid file";}?>
5 Cookies
5.1 Create cookie setcookie() function
Syntax: setcookie(name, value, expire, path, domain);
5.2 Retrieve cookie value
Use the isset() function to confirm whether a cookie has been set:
";}else{echo "Welcome guest !
";}?>5.3 Delete cookies
6 Session variables
6.1 Start session
6.2 Storing session variables
6.3 Terminate session
7 mail() function is used to send emails from scripts.
Syntax: mail(to, subject, message, headers, parameters)
Parameter
Description
to
Required. Specify email recipients.
subject
Required. Specifies the subject of the email. Note: This parameter cannot contain any newline characters.
message
Required. Define the message to be sent. LF(
) to separate lines.
headers
Optional. Specify additional headers, such as From, Cc, and Bcc. CRLF(
) separates additional headers.
parameters
Optional. Specifies additional parameters for the mailer.
7.1 Example
?>

PHP remains important in modern web development, especially in content management and e-commerce platforms. 1) PHP has a rich ecosystem and strong framework support, such as Laravel and Symfony. 2) Performance optimization can be achieved through OPcache and Nginx. 3) PHP8.0 introduces JIT compiler to improve performance. 4) Cloud-native applications are deployed through Docker and Kubernetes to improve flexibility and scalability.

PHP is suitable for web development, especially in rapid development and processing dynamic content, but is not good at data science and enterprise-level applications. Compared with Python, PHP has more advantages in web development, but is not as good as Python in the field of data science; compared with Java, PHP performs worse in enterprise-level applications, but is more flexible in web development; compared with JavaScript, PHP is more concise in back-end development, but is not as good as JavaScript in front-end development.

PHP and Python each have their own advantages and are suitable for different scenarios. 1.PHP is suitable for web development and provides built-in web servers and rich function libraries. 2. Python is suitable for data science and machine learning, with concise syntax and a powerful standard library. When choosing, it should be decided based on project requirements.

PHP is a scripting language widely used on the server side, especially suitable for web development. 1.PHP can embed HTML, process HTTP requests and responses, and supports a variety of databases. 2.PHP is used to generate dynamic web content, process form data, access databases, etc., with strong community support and open source resources. 3. PHP is an interpreted language, and the execution process includes lexical analysis, grammatical analysis, compilation and execution. 4.PHP can be combined with MySQL for advanced applications such as user registration systems. 5. When debugging PHP, you can use functions such as error_reporting() and var_dump(). 6. Optimize PHP code to use caching mechanisms, optimize database queries and use built-in functions. 7

The reasons why PHP is the preferred technology stack for many websites include its ease of use, strong community support, and widespread use. 1) Easy to learn and use, suitable for beginners. 2) Have a huge developer community and rich resources. 3) Widely used in WordPress, Drupal and other platforms. 4) Integrate tightly with web servers to simplify development deployment.

PHP remains a powerful and widely used tool in modern programming, especially in the field of web development. 1) PHP is easy to use and seamlessly integrated with databases, and is the first choice for many developers. 2) It supports dynamic content generation and object-oriented programming, suitable for quickly creating and maintaining websites. 3) PHP's performance can be improved by caching and optimizing database queries, and its extensive community and rich ecosystem make it still important in today's technology stack.

In PHP, weak references are implemented through the WeakReference class and will not prevent the garbage collector from reclaiming objects. Weak references are suitable for scenarios such as caching systems and event listeners. It should be noted that it cannot guarantee the survival of objects and that garbage collection may be delayed.

The \_\_invoke method allows objects to be called like functions. 1. Define the \_\_invoke method so that the object can be called. 2. When using the $obj(...) syntax, PHP will execute the \_\_invoke method. 3. Suitable for scenarios such as logging and calculator, improving code flexibility and readability.


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