``` import os import shutil from sklearn.model_selection import train_test_split import pandas as pd # 定义源目录路径 source_folder = 'C:/Users\Lenovo\Desktop\crcw不同端12k在0负载下\风扇端' subfolders = ["内圈故障", "球故障"] # 创建目标文件夹结构 target_folders = { 'train': '训练集', 'val': '验证集', 'test': '测试集' } os.makedirs('划分后的数据', exist_ok=True) for key, folder in target_folders.items(): for subfolder in subfolders: path = os.path.join('划分后的数据', folder, subfolder) os.makedirs(path, exist_ok=True) # 遍历每个子文件夹并读取CSV文件 all_data = [] for subfolder in subfolders: folder_path = os.path.join(source_folder, subfolder) files = [f for f in os.listdir(folder_path) if f.endswith('.csv')] # 将所有数据加载到列表中 for file in files: data = pd.read_csv(os.path.join(folder_path, file)) all_data.append((data, subfolder)) # 划分数据集 train_val, test = train_test_split(all_data, test_size=0.2, random_state=42) train, val = train_test_split(train_val, test_size=0.25, random_state=42) # 即最终比例为6:2:2 # 移动文件至对应的目标文件夹 def move_files(data_list, target_dir): for data, label in data_list: filename = f"{label}_{hash(str(data.iloc[0].values))}.csv" # 确保唯一性 save_path = os.path.join(target_folders[target_dir], label, filename) data.to_csv(save_path, index=False) move_files(train, 'train') move_files(val, 'val') move_files(test, 'test') print("数据集已成功划分为训练集、验证集和测试集！")```这段代码中在哪定义目标文件夹呢