1.dataset

Dataset：提供一种方式去获取数据及其label

                1.如何获取每一个数据及其label
                2.告诉我们总共有多少个数据

Dataloader：为后面的网络提供不同的数据形式

from torch.utils.data import Dataset
from PIL import  Image
import os  #operatopm system
class mydata(Dataset):
    def __init__(self,root_dir,label_dir):
        self.root_dir = root_dir
        self.label_dir = label_dir
        self.path = os.path.join(self.root_dir,self.label_dir)
        self.img_path =os.listdir(self.path)
    def __getitem__(self, index):
        img_name = self.img_path[index]
        img_item_path = os.path.join(self.root_dir,self.label_dir,img_name)
        img = Image.open(img_item_path)
        label = self.label_dir
        return img,label
    def __len__(self):
        return len(self.img_path)
root_dir = 'data/dataset/train'
ants_label_dir = 'ants'
bees_label_dir = 'bees'
ants_dataset = mydata(root_dir,ants_label_dir)
bees_dataset = mydata(root_dir,bees_label_dir)
train_dataset = ants_dataset + bees_dataset
print(len(train_dataset))
print(len(ants_dataset))
print(len(bees_dataset))
img,label = train_dataset[123]
img.show()