


Explanation of the meaning of common PHP error prompts (practical! Worth collecting)_php skills
This article explains the meaning of common PHP error prompts. Share it with everyone for your reference, the details are as follows:
When I was learning PHP, I often encountered various error prompts. It felt good to see this error prompt and explanation today. I now turn it over for us to learn from. hehe. . . . .
1. Notice: Undefined variable: variable name in
Note: An undefined variable is used
2. Parse error: syntax error, unexpected T_ELSE in
If () {
}Else if () {
}
Echo $test;
Else {
}
Note: The if else if else sentence structure is wrong
3. Parse error: syntax error, unexpected $end in D
Note: Usually the curly braces do not match
4. Parse error: syntax error, unexpected T_STRING in
Note: Usually I forget to write the semicolon at the end of the sentence
5. Warning: Invalid argument supplied for foreach() in
Note: The first parameter of foreach must be an array
6. Warning: mysql_fetch_assoc(): supplied argument is not a valid MySQL result resource in
Note: This means that the previous execution of SQL failed to return. Generally, it may be an error in the SQL statement. If the analysis cannot come out, you can just print out Mysql_error (); to see where the error is specifically
7. No database selected
Note: Usually there is no connection to the database
8. Warning: mysql_connect() [function.mysql-connect]: Access denied for user 'root'@'localhost' (using password : YES) in ….. on line 3
Access denied for user 'root'@'localhost' (using password: YES)
Note: The database username and password are wrong
9. Unknown database 'cms07261′
Note: There is no such database
10. Table 'cms0726.test' doesn't exist
Note: The table does not exist
11. Unknown column 'abc' in 'field list'
Note: Field does not exist
12. Column count doesn't match value count at row 1
Note: The number of field values in the sql statement is different from the number of field names
13. Warning: Wrong parameter count for function name in
Note: The number of function logarithms is missing
14. Fatal error: Smarty error: [in message_list.html line 22]: syntax error: 'foreach: item' must be a variable name (literal string)
Note: Look at the line number, it means that the item after foreach must be followed by a variable name, without $, it is a string (note: no single or double quotes)
15. Fatal error: Smarty error: [in message_list.html line 24]: syntax error: unrecognized tag: msg.message_id
Note: $
16. Warning: Smarty error: unable to read resource: "message_list1.html" in
Note: The template file cannot be found. Check whether the file name is written incorrectly or the file is stored in another directory.
17. Fatal error: Cannot redeclare get_sort1() (previously declared in
Note: The function has been defined and cannot be redefined
I hope this article will be helpful to everyone in PHP programming.

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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