10 mistakes for beginners to PHP and how to avoid them

In the process of learning PHP, beginners often make some mistakes. These errors can cause their code to run slowly or even crash. This article will list 10 common mistakes made by beginners in PHP and provide some ways to avoid them.

1. Not learning basic knowledge
   PHP is a programming language. To master it proficiently, you need to build on solid basic knowledge. If you skip these basics and go straight to advanced tutorials, you will be stuck because you lack the basic knowledge. It is recommended that beginners first lay a solid foundation in the process of learning PHP.
2. No error handling
   Whether you are writing PHP or writing code in other programming languages, errors will occur. If these errors are not handled, the program may run slowly or crash. When writing PHP code, be sure to handle errors to ensure the robustness of your program.
3. Using undefined variables
   Beginners often forget to define variables and use them directly. This error will cause PHP to report errors and make the program run slowly. It is recommended that before using variables, you must first ensure that these variables have been defined.
4. Concatenating strings too frequently
   In PHP, it is very convenient to concatenate strings, but this operation is very time-consuming. If the program frequently concatenates strings, it will cause the program to become very slow. When writing PHP code, you must consider performance issues and avoid excessive concatenation operations on strings. You can use PHP's string buffer to optimize the code.
5. Forgot to release memory
   Although PHP's garbage collection mechanism is excellent, in some extreme cases, programmers also need to manually release memory. If the memory is not released, it will cause a memory leak and eventually cause the program to crash. When writing PHP code, pay attention to the use of dynamic memory and release memory in a timely manner.
6. Perform unsafe operations on the database
   When using PHP to operate the database, you must pay attention to prevent SQL injection attacks. Because PHP does not overdo input validation, this leaves an opportunity for attackers to attack. SQL injection attacks can be avoided by validating the input data.
7. Improper use of loops
   Loop statements are an essential part of PHP, they can be used to perform certain operations repeatedly. But if the number of loops is too many, program performance will decrease. When writing PHP code, consider the number of loops and avoid too many loops.
8. Referencing the wrong file path
   In PHP, using the wrong file path or file name to read a file will cause the program to run abnormally or even crash. When writing PHP code, it is important to ensure that the path and file name of the file being read is correct.
9. Incorrect operations on arrays
   In PHP, arrays are a very commonly used data structure. However, errors must also be avoided when operating on arrays. For example, when using an array, make sure that the subscripts of the array are correct and do not go out of bounds. In addition, ensure the uniqueness of the key name.
10. No code optimization
    When writing PHP code, performance issues should be taken into consideration and unnecessary operations in the code should be reduced as much as possible. Code optimization can improve the running speed of the program, reduce running memory, etc.

The above are 10 mistakes that beginners often make when learning PHP. Avoiding these errors can improve program robustness and code efficiency. Therefore, beginners must keep these mistakes in mind and learn from them when learning PHP.

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