ndarray
basic operation
1  from numpy import * 
creation
arange, random.rand, random.randint, linspace, ones, zeros, empty, logspace
slice

a[…, i]
… represent unspecified dim

np.split(a, N)
split a into evenly N parts

np.split(a, [])
split a at certain index
concat
 np.vstack(a, b)
 np.hstack(a, b)
 np.concatenate(a, b, axis = ?)
 np.stack(a, b) Note: Stack in a new dimension
 np.fliplr()
 np.flipud()
basic math operation

np.dot
Note: calculate dot product of two vectors

power
1  from numpy import * 
random
1  import python.random as random 
useful
 operation on mask ndarray
1  a = np.arange(10) 
Numpy Cheatsheet
Those two are copied from BHu by me and the origin of which are shown in the pics.