mindspore.dataset.PKSampler

class mindspore.dataset.PKSampler(num_val, num_class=None, shuffle=False, class_column='label', num_samples=None)[source]

Samples K elements for each P class in the dataset.

Parameters:

num_val (int) – Number of elements to sample for each class.
num_class (int, optional) – Number of classes to sample. Default: None , sample all classes. This parameter is not currently supported.
shuffle (bool, optional) – Whether to shuffle the class IDs. Default: False.
class_column (str, optional) – Name of column with class labels for MindDataset. Default: 'label'.
num_samples (int, optional) – The number of samples to draw. Default: None , which means sample all elements.

Raises:

TypeError – If shuffle is not of type bool.
TypeError – If class_column is not of type str.
TypeError – If num_samples is not of type int.
NotImplementedError – If num_class is not None.
RuntimeError – If num_val is not a positive value.
ValueError – If num_samples is a negative value.

Examples

>>> import mindspore.dataset as ds
>>> # creates a PKSampler that will get 3 samples from every class.
>>> sampler = ds.PKSampler(3)
>>> dataset = ds.ImageFolderDataset(image_folder_dataset_dir,
...                                 num_parallel_workers=8,
...                                 sampler=sampler)