pytorch dataloader to numpy array
# index is the specific data your want in dataloader
import numpy as np
def transfer_dataloader(dataloader, index=0):
cache_list = list(iter(dataloader))
assert len(cache_list) > 0
assert index < len(cache_list[0])
result_list = np.array(list(map(lambda x: x[index].numpy(), cache_list)))
return result_list