ComposeDataset¶

class paddle.io. ComposeDataset ( datasets ) [source]

A Dataset which composes fields of multiple datasets.

This dataset is used for composing fields of multiple map-style datasets of same length.

Parameters

datasets (list of Dataset) – List of datasets to be composed.

Returns

A Dataset which composes fields of multiple datasets.

Return type

Dataset

Examples

>>> import numpy as np
>>> import paddle
>>> from paddle.io import Dataset, ComposeDataset


>>> # define a random dataset
>>> class RandomDataset(Dataset):
...     def __init__(self, num_samples):
...         self.num_samples = num_samples
...
...     def __getitem__(self, idx):
...         image = np.random.random([32]).astype('float32')
...         label = np.random.randint(0, 9, (1, )).astype('int64')
...         return image, label
...
...     def __len__(self):
...         return self.num_samples
...
>>> dataset = ComposeDataset([RandomDataset(10), RandomDataset(10)])
>>> for i in range(len(dataset)):
...     image1, label1, image2, label2 = dataset[i]
...     # do something