如何调整Python的get_records()函数加载MIT-BIH NSRDB等PhysioNet数据库？

Hey there! Let's figure out how to tweak that get_records() function in your mitdb.py to work with NSRDB and other PhysioNet databases. Here's a practical, flexible approach:

First, Make Sure You Have the Right Tooling #

Most PhysioNet database interactions in Python rely on the wfdb library—if you don't have it installed yet, run:

pip install wfdb

Modify the get_records() Function for Universal Use #

The original function was hardcoded for the MIT-BIH Arrhythmia Database. We'll refactor it to accept parameters that let you target any public PhysioNet database, including NSRDB. Here's the adjusted code:

import os
import wfdb

def get_records(database_name='mitdb', data_dir='datasets', records=None):
    """
    Download and load records from any public PhysioNet database.
    
    Args:
        database_name (str): Name of the PhysioNet database (e.g., 'nsrdb' for Normal Sinus Rhythm Database)
        data_dir (str): Directory to store downloaded data (will be created if it doesn't exist)
        records (list, optional): Specific record IDs to download. If None, downloads all records in the database.
    
    Returns:
        list: List of loaded WFDB Record objects
    """
    # Create the data directory if it doesn't exist
    os.makedirs(data_dir, exist_ok=True)
    
    # Get all record names if none are specified
    if records is None:
        record_names = wfdb.get_record_list(database_name)
    else:
        record_names = records
    
    # Download the requested records
    wfdb.dl_database(
        database=database_name,
        dl_dir=data_dir,
        records=record_names
    )
    
    # Load each record into memory
    loaded_records = []
    for record_name in record_names:
        record_path = os.path.join(data_dir, record_name)
        rec = wfdb.rdrecord(record_path)
        loaded_records.append(rec)
    
    return loaded_records

Key Changes Explained #

• Parameter Flexibility: We added database_name (defaults to 'mitdb' for backward compatibility) so you can switch to 'nsrdb', 'ptbdb', or any other public PhysioNet database.
• Dynamic Record Lists: Instead of hardcoding record IDs, we use wfdb.get_record_list(database_name) to fetch all records for the target database automatically.
• Auto-Create Directories: The function now makes sure your data_dir exists, so you don't have to manually create folders.
• Reusable Download Logic: wfdb.dl_database() is PhysioNet's official method for downloading database files, so it works across all their public datasets.

How to Use It for NSRDB #

To download and load the Normal Sinus Rhythm Database, just call the function like this:

nsrdb_records = get_records(database_name='nsrdb', data_dir='datasets/nsrdb')

Quick Notes #

• For restricted PhysioNet databases (those requiring login), add wfdb.set_auth("your_username", "your_password") before calling the function.
• If you only need specific records from NSRDB, pass them as a list: get_records('nsrdb', 'datasets/nsrdb', records=['16265', '16272'])

内容的提问来源于stack exchange，提问作者Ahmed K. Moustafa