In Python, the function of the -= operator is to subtract the value of the variable from the right and assign the result to the variable, which is equivalent to a=a-b. 1) It is suitable for data types such as integers, floating point numbers, lists and strings. 2) Pay attention to type consistency, performance and code readability when using it. 3) The string is immutable and similar effects need to be achieved through slice operations. This operator simplifies code and improves readability and efficiency.

Strings in Python are immutable sequence types. 1) You can use single quotes, double quotes, triple quotes or str() functions to create strings. 2) The operation string can be done by splicing, formatting, searching, replacing and slicing. 3) Pay attention to immutability and encoding issues when processing strings. 4) Performance optimization can be performed using the join method instead of frequent splicing. 5) It is recommended to keep the code readable and use regular expressions to simplify complex operations.

The easiest way to calculate list length in Python is to use the len() function. 1) The len() function is suitable for lists, strings, tuples, dictionaries, etc., and returns the number of elements. 2) Although custom length calculation function is feasible, it is inefficient and is not recommended to use it in practical applications. 3) When processing large data sets, you can first calculate the length to avoid repeated calculations and improve performance. Using the len() function is simple, fast and reliable, and is the best practice for calculating list lengths.

There are three main ways to deal with asynchronous operations in JavaScript: 1. Callback functions, which can easily lead to callback hell; 2. Promise, which provides clearer process expression, but may be lengthy when processing multiple operations; 3. async/await, which is based on Promise, and the code is more intuitive, but performance issues need to be paid attention to.

Reducing the use of global variables in C can be achieved by: 1. Using encapsulation and singleton patterns to hide data and limit instances; 2. Using dependency injection to pass dependencies; 3. Using local static variables to replace global shared data; 4. Reduce the dependence of global variables through namespace and modular organization of code.

In C, the bit field is a structure member that specifies the number of bits, used to save memory and directly manipulate hardware. Example: structMyStruct{inta:2;intb:5;intc:1;}. The advantage of bit domains is memory savings, but there are cross-platform issues, access restrictions and assignments that require caution. Example of usage: structStateMachine{unsignedintpower:1;unsignedintmode:2;unsignedinterror:1;}. Performance recommendations include arranging bit fields by size, avoiding overuse and adequate testing.

The syntax of the trigonometric operator in C is condition?expression1:expression2, which is used to select and execute different expressions according to the condition. 1) Basic usage example: intmax=(x>y)?x:y, used to select the larger value in x and y. 2) Example of nested usage: intresult=(a>0&&b>0)?a b:(a==0||b==0)?a*b:a-b, used to perform different operations according to different conditions. 3) Error handling example: std::stringerrorMessage=(errorCode==0)?"Successful&quo

The usage of logical non-operator! in C includes: 1) Basic usage: inverse the Boolean value; 2) Conditional judgment: simplify the code, such as checking whether the container is empty; 3) Loop control: processing elements that do not meet the conditions; 4) Function return value processing: determine whether the operation has failed. Pay attention to potential pitfalls such as pointer processing and operator priority when using!, but it can help write more concise and efficient code.