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Dataset,dataloder analysis

Only the datasets downloaded from the Internet are stored in the cifar_data_test folder created by ourselves.

Cifar-10-python.tar.gz

Due to the existence of download=True: an extra cifar-10-batches-py

Dataset = torchvision.datasets.CIFAR10 (root='./cifar_data_test',download=True)

Print (dataset) can see that the dataset defaults to train=True

Train=False is used to select a training set or a test set.

Dataset = torchvision.datasets.CIFAR10 (root='./cifar_data_test',train=False,download=True) print (dataset) print (dataset.classes) print (dataset.data.shape, "\ n", dataset.data)

Transform

One: because CIFAR10 is tensor, it is useless to it.

Second: the transform added to dataset does not normalize the dataset, but only when dataloader

Import torchvision.datasetsimport torchvision.transforms as transformsfrom torch.utils.data import DataLoader#transform has two operations, one is to change it into tensor form that pythonj is easy to handle. The second is to normalize tensor transform= transforms.Compose ([transforms.ToTensor (), transforms.Normalize ((0.1307,), (0.3081,))]) dataset = torchvision.datasets.CIFAR10 (root='./cifar_data_test',train=True,download=True,transform=transform) print (dataset.data) # unnormalized train_loader = DataLoader (dataset,shuffle=False,batch_size=32) # dataloader has no transform parameter for img Target in train_loader:print (img) # data normalization above is the content of the article "dataset and dataloader instance Analysis of pytorch" I believe we all have a certain understanding. I hope the content shared by the editor will be helpful to you. If you want to know more about the relevant knowledge, please pay attention to the industry information channel.

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