Found a total of 10000 related content
Python Cryptography Library Usage
Article Introduction：The Python encryption library is used as follows: 1. Symmetric encryption is recommended to use the Fernet module in the cryptography library. The key is generated by generate_key() and the data is encrypted and decrypted with encrypt()/decrypt(); 2. The hashlib library can be used to calculate hashlib, and the SHA256 algorithm is preferred and the hash value is obtained through hexdigest(). Pay attention to avoiding MD5 and SHA1; 3. Asymmetric encryption can use the RSA function of cryptography to generate key pairs through generate_private_key(), and use public key encryption and private key decryption. Note that filling schemes such as OAEP must be used and only suitable
2025-07-17
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522
How to check if a php function exists?
Article Introduction：In PHP, you should use the function_exists() function. This function is used to check whether a normal function has been defined, return a Boolean value, and if it exists, return true, otherwise return false; when using it, you need to pass in the correct function name string, such as function_exists('my_function'); if you need to determine whether the class method exists, method_exists() should be used to pass in the class name, method name or object instance and method name; note that the function name is case-insensitive and cannot be used to detect disabled functions.
2025-07-22
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166
How to check if a function exists in PHP?
Article Introduction：In PHP, you should use the function_exists() function and pay attention to its scope of application and limitations. This method determines whether it exists by passing in the function name string. It is suitable for user-defined functions, extended functions and functions in namespace (requires a complete path); but it is not suitable for class methods or language structures. For inspection of class methods or object methods, the method_exists() function should be used to pass the class name or object instance respectively. In addition, it is necessary to avoid misuse of language structures such as echo, ensuring accurate spelling of function names, and preventing repeated definitions.
2025-07-07
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672
What is the role of spl_autoload_register() in PHP's class autoloading mechanism?
Article Introduction：spl_autoload_register() is a core function used in PHP to implement automatic class loading. It allows developers to define one or more callback functions. When a program tries to use undefined classes, PHP will automatically call these functions to load the corresponding class file. Its main function is to avoid manually introducing class files and improve code organization and maintainability. Use method is to define a function that receives the class name as a parameter, and register the function through spl_autoload_register(), such as functionmyAutoloader($class){require_once'classes/'.$class.'.php';}spl_
2025-06-09
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386
How can you check if a function exists in PHP?
Article Introduction：To check whether the function in PHP exists, the function_exists() function is mainly used. 1. function_exists() receives a string parameter to determine whether the specified function has been defined; 2. This method is valid for both user-defined functions and built-in functions; 3. The function name is case-insensitive when judging; 4. It is often used in scenarios such as plug-in development, conditional execution, and maintaining backward compatibility; 5. In object-oriented programming, method_exists() and class_exists() should be used to check whether the method and class exist respectively. These functions help avoid fatal errors and improve code robustness and flexibility.
2025-07-21
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896
How to Access Class Properties from Strings in Python?
Article Introduction：This article presents a technique for dynamically accessing class properties based on strings in Python using the getattr() function. The primary issue addressed is how to retrieve and utilize specific class properties based on variable string values
2024-10-23
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490
How to get the name of the current function in PHP?
Article Introduction：There are three methods to obtain the current execution function name in PHP: 1.\_\_FUNCTION\_\_The name of the magic constant when returning the function definition is suitable for ordinary functions; 2.\_\_METHOD\_\_ is used to return "class name:: method name" in class methods, which can extract the method name through string processing; 3.debug\_backtrace() can dynamically obtain the call stack information to obtain the current execution function name but the performance is low, and it is recommended to be used in debugging scenarios. \_\_FUNCTION\_\_ and \_\_METHOD\_ are simpler and more efficient in their respective contexts and debug\_backtrace() provides a more flexible but heavier solution.
2025-07-06
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216
