Created
February 27, 2020 04:19
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collate_fn for PyTorch DataLoader
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import torch | |
from torch.utils.data import Dataset, DataLoader | |
import numpy as np | |
class MyDataset(Dataset): | |
def __init__(self): | |
x = np.random.rand(1000, 3) # 1000 3-dim samples | |
self.x = [x[i].tolist() for i in range(1000)] | |
y = np.random.randint(low=0, high=2, size=(1000,)) | |
self.y = [y[i] for i in range(1000)] | |
def __len__(self): | |
return len(self.x) | |
def __getitem__(self, idx): | |
return self.x[idx], self.y[idx] | |
def collate_fn(batch): | |
data_list, label_list = [], [] | |
for _data, _label in batch: | |
data_list.append(_data) | |
label_list.append(_label) | |
return torch.Tensor(data_list), torch.LongTensor(label_list) | |
if __name__ == "__main__": | |
dataset = MyDataset() | |
print(len(dataset)) | |
print(dataset[-1]) | |
dataloader = DataLoader(dataset, batch_size=3, shuffle=False, collate_fn=collate_fn) | |
for data, label in dataloader: | |
print(type(data)) | |
print(data) | |
print(type(label)) | |
print(label) | |
break |
Thank you very much!
I am learning Pytorch and I don't know how to Dataloader 15002828 data input the model. Your example teache me how to do that. Thank you a thousand times.
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explicit definition of
collate_fn
is not required ifself.x
andself.y
arenumpy
arrays already.collate_fn=None
will create two tensors for each batch.