有没有一种方法可以从HDF5数据集中删除行? [英] Is there a way of removing rows from a HDF5 dataset?
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问题描述
我创建了一个约有210万个实例的H5PY数据集.问题是我已经填满了除最后一行以外的所有行.我想删除最后一行,但不确定这样做是否可行或安全.
I have created a H5PY dataset, with around 2.1 million instances. The issue is I have filled all the rows apart from the last one. I want to remove the last row but unsure if it is feasible or safe to do.
这是如何创建数据集的摘录:
This is a snippet of how the dataset is created:
shape = (dataset_length, args.batch_size, 2048, 1, 1)
with h5py.File(path, mode='a') as hdf5_file:
array_40 = hdf5_file.create_dataset(
f'{phase}_40x_arrays', shape, maxshape=(None, args.batch_size, 2048, 1, 1)
# either new or checkpointed file exists
# load file and create references to exisitng h5 datasets
with h5py.File(path, mode='r+') as hdf5_file:
array_40 = hdf5_file[f'{phase}_40x_arrays']
for i, (inputs40x, labels) in enumerate(dataloaders_dict):
inputs40x = inputs40x.to(device)
x40 = resnet(inputs40x)
array_40[batch_idx, ...] = x40.cpu()
hdf5_file.flush()
我不确定是否需要将所有实例复制到新数据集中.我尝试调整大小,但这没用...
I'm not really sure if I need to copy all instances to a new dataset. I tried resizing, but that didn't work...
干杯
推荐答案
这是一个非常简单的示例,用于演示一个数据集的 dataset.resize()
.
Here is a very simple example to demonstrate dataset.resize()
for one dataset.
import numpy as np
import h5py
arr = np.random.rand(100).reshape(20,5)
with h5py.File('SO_61487687.h5', mode='a') as h5f:
h5f.create_dataset('array1', data=arr, maxshape=(None, 5) )
with h5py.File('SO_61487687.h5', mode='r+') as h5f:
print ('Before:', h5f['array1'].shape)
h5f['array1'].resize(10,axis=0)
print ('After:', h5f['array1'].shape)
h5f.flush()
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