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.

When you open PyCharm for the first time, you should first create a new project and select a virtual environment, and then be familiar with the editor area, toolbar, navigation bar, and status bar. Set up Darcula themes and Consolas fonts, use smart tips and debugging tools to get more efficient, and learn Git integration.

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.

Create a SQLite database in Python using the sqlite3 module. The steps are as follows: 1. Connect to the database, 2. Create a cursor object, 3. Create a table, 4. Submit a transaction, 5. Close the connection. This is not only simple and easy to do, but also includes optimizations and considerations such as using indexes and batch operations to improve performance.

str is a built-in type used in Python to represent text data, i.e. strings. 1. A string is an immutable sequence and cannot be modified. 2. Python's string encoding is Unicode by default, and supports global applications. 3. String operations include splicing, formatting, slicing and method calls. 4. When processing a large number of strings, using the join method or bytearray can improve performance. 5. When processing text data from different sources, using the chardet library to detect encoding can avoid decoding errors.

Setting the location of the interpreter in PyCharm can be achieved through the following steps: 1. Open PyCharm, click the "File" menu, and select "Settings" or "Preferences". 2. Find and click "Project:[Your Project Name]" and select "PythonInterpreter". 3. Click "AddInterpreter", select "SystemInterpreter", browse to the Python installation directory, select the Python executable file, and click "OK". When setting up the interpreter, you need to pay attention to path correctness, version compatibility and the use of the virtual environment to ensure the smooth operation of the project.

To develop a complete Python Web application, follow these steps: 1. Choose the appropriate framework, such as Django or Flask. 2. Integrate databases and use ORMs such as SQLAlchemy. 3. Design the front-end and use Vue or React. 4. Perform the test, use pytest or unittest. 5. Deploy applications, use Docker and platforms such as Heroku or AWS. Through these steps, powerful and efficient web applications can be built.