How to retain decimal places in Python

shutil.rmtree() is a function in Python that recursively deletes the entire directory tree. It can delete specified folders and all contents. 1. Basic usage: Use shutil.rmtree(path) to delete the directory, and you need to handle FileNotFoundError, PermissionError and other exceptions. 2. Practical application: You can clear folders containing subdirectories and files in one click, such as temporary data or cached directories. 3. Notes: The deletion operation is not restored; FileNotFoundError is thrown when the path does not exist; it may fail due to permissions or file occupation. 4. Optional parameters: Errors can be ignored by ignore_errors=True

To create a Python virtual environment, you can use the venv module. The steps are: 1. Enter the project directory to execute the python-mvenvenv environment to create the environment; 2. Use sourceenv/bin/activate to Mac/Linux and env\Scripts\activate to Windows; 3. Use the pipinstall installation package, pipfreeze>requirements.txt to export dependencies; 4. Be careful to avoid submitting the virtual environment to Git, and confirm that it is in the correct environment during installation. Virtual environments can isolate project dependencies to prevent conflicts, especially suitable for multi-project development, and editors such as PyCharm or VSCode are also

Install the corresponding database driver; 2. Use connect() to connect to the database; 3. Create a cursor object; 4. Use execute() or executemany() to execute SQL and use parameterized query to prevent injection; 5. Use fetchall(), etc. to obtain results; 6. Commit() is required after modification; 7. Finally, close the connection or use a context manager to automatically handle it; the complete process ensures that SQL operations are safe and efficient.

Use multiprocessing.Queue to safely pass data between multiple processes, suitable for scenarios of multiple producers and consumers; 2. Use multiprocessing.Pipe to achieve bidirectional high-speed communication between two processes, but only for two-point connections; 3. Use Value and Array to store simple data types in shared memory, and need to be used with Lock to avoid competition conditions; 4. Use Manager to share complex data structures such as lists and dictionaries, which are highly flexible but have low performance, and are suitable for scenarios with complex shared states; appropriate methods should be selected based on data size, performance requirements and complexity. Queue and Manager are most suitable for beginners.

Use boto3 to upload files to S3 to install boto3 first and configure AWS credentials; 2. Create a client through boto3.client('s3') and call the upload_file() method to upload local files; 3. You can specify s3_key as the target path, and use the local file name if it is not specified; 4. Exceptions such as FileNotFoundError, NoCredentialsError and ClientError should be handled; 5. ACL, ContentType, StorageClass and Metadata can be set through the ExtraArgs parameter; 6. For memory data, you can use BytesIO to create words

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Weakreferencesexisttoallowreferencingobjectswithoutpreventingtheirgarbagecollection,helpingavoidmemoryleaksandcircularreferences.1.UseWeakKeyDictionaryorWeakValueDictionaryforcachesormappingstoletunusedobjectsbecollected.2.Useweakreferencesinchild-to

Use the Pythonschedule library to easily implement timing tasks. First, install the library through pipinstallschedule, then import the schedule and time modules, define the functions that need to be executed regularly, then use schedule.every() to set the time interval and bind the task function. Finally, call schedule.run_pending() and time.sleep(1) in a while loop to continuously run the task; for example, if you execute a task every 10 seconds, you can write it as schedule.every(10).seconds.do(job), which supports scheduling by minutes, hours, days, weeks, etc., and you can also specify specific tasks.