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74 lines
2.4 KiB
74 lines
2.4 KiB
# Copyright (c) 2020 PaddlePaddle Authors. All Rights Reserved.
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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from __future__ import print_function
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import paddle.dataset.common
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__all__ = ["Dataset"]
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class Dataset(object):
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"""
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An abstract class to encapsulates methods and behaviors of datasets.
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All datasets in map-style(dataset samples can be get by a given key)
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should be a subclass of `paddle.io.Dataset`. All subclasses should
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implement following methods:
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:code:`__getitem__`: get sample from dataset with a given index. This
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method is required by reading dataset sample in :code:`paddle.io.DataLoader`.
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:code:`__len__`: return dataset sample number. This method is required
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by some implements of :code:`paddle.io.BatchSampler`
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see :code:`paddle.io.DataLoader`.
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Examples:
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.. code-block:: python
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import numpy as np
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from paddle.io import Dataset
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# define a random dataset
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class RandomDataset(Dataset):
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def __init__(self, num_samples):
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self.num_samples = num_samples
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def __getitem__(self, idx):
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image = np.random.random([784]).astype('float32')
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label = np.random.randint(0, 9, (1, )).astype('int64')
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return image, label
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def __len__(self):
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return self.num_samples
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dataset = RandomDataset(10)
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for i in range(len(dataset)):
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print(dataset[i])
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"""
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def __init__(self):
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pass
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def __getitem__(self, idx):
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raise NotImplementedError("'{}' not implement in class "\
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"{}".format('__getitem__', self.__class__.__name__))
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def __len__(self):
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raise NotImplementedError("'{}' not implement in class "\
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"{}".format('__len__', self.__class__.__name__))
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