What are the keywords in php

php keywords include echo, if, else, elseif, for, while, do-while, switch, case, default, break, continue, function, return, include, require, class, public, private, protected etc. Detailed introduction: 1. The echo keyword is used to output text or variable values ​​on the web page; 2. if, else keywords, etc.

The operating environment of this tutorial: Windows 10 system, PHP8.1.3 version, Dell G3 computer.

PHP is a widely used server-side scripting language used for developing dynamic web pages and applications. In PHP, keywords are reserved words with special meanings that are used to define the grammatical structure and functions of the language. This article will introduce some common PHP keywords and their uses.

1. echo: used to output text or variable values ​​on the web page. Text, HTML tags and variable values ​​can be combined for output.

2. if, else, elseif: used for conditional statements, executing different code blocks according to the true or false condition.

3. for, while, do-while: used in loop structures to repeatedly execute a section of code until specific conditions are met.

4. switch, case, default: used in multi-branch structures to execute different code blocks according to different conditions.

5. break: used to jump out of a loop or switch statement and end the execution of the current code block.

6. continue: Used to skip the remaining code of the current loop and continue executing the next loop.

7. function: used to define functions and encapsulate a piece of code into a reusable module.

8. return: used to return a value from the function and end the execution of the function.

9. include, require: used to include and execute external files, and can embed code in one file into another file.

10. class, public, private, protected: used in object-oriented programming to define access permissions for classes and their attributes and methods.

11. extends, implements: used for class inheritance and interface implementation.

12. static: used to define static properties and methods, which can be accessed directly without instantiating the class.

13. global: used to access global variables within a function.

14. const: used to define constants, which cannot be modified once defined.

15. namespace: used to organize code into namespaces to avoid naming conflicts.

The above are some common PHP keywords, which have special meanings and functions in the PHP language. Proficiency in these keywords can help developers better use the PHP language to develop web pages and applications.

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