Learn to load dataset in batches

from module import *, means import all file in this directories

Function()() 嵌套函数，第二个括号代表内嵌函数的变量

HDF5 file: https://www.neonscience.org/about-hdf5
similar way of storing in computer, groups<-->folder or directories, datasets<-->file.
metadata is 'data about data'
use hdf5 file in python: https://www.geeksforgeeks.org/hdf5-files-in-python/

numpy.unique(),numpy.argsort()(从小到大),numpy.split()
skimage.view_as_windows, ndarray.tolist()

The continue statement in Python returns the control to the beginning of the while loop. 
The continue statement rejects all the remaining statements in the current iteration of the loop 
and moves the control back to the top of the loop. The continue statement can be used in both while and for loops.