import os

def change_ext_to_csv(directory='.'):
    for filename in os.listdir(directory):
        if filename.endswith('.txt') or filename.endswith('.TXT'):
            base = os.path.splitext(filename)[0]  # 分离文件名和扩展名
            new_name = f"{base}.csv"
            try:
                os.rename(
                    os.path.join(directory, filename),
                    os.path.join(directory, new_name)
                )
                print(f'Renamed: "{filename}" → "{new_name}"')
            except Exception as e:
                print(f'Failed to rename "{filename}": {str(e)}')

if __name__ == '__main__':
    change_ext_to_csv()  # 默认当前目录