vstack and hstack in numpy code example

Example 1: np vstack

>>> a = np.array([1, 2, 3])
>>> b = np.array([2, 3, 4])
>>> np.vstack((a,b))
array([[1, 2, 3],
       [2, 3, 4]])
       
>>> a = np.array([[1], [2], [3]])
>>> b = np.array([[2], [3], [4]])
>>> np.vstack((a,b))
array([[1],
       [2],
       [3],
       [2],
       [3],
       [4]])

Example 2: np.hstack

# np.hstack concatenates arrays column-wise

a = np.array([1], [2], [3]) #read as a vector, i.e. a column
b = np.array([4], [5], [6]) #read as a vector, i.e. a column 
							#concatenated to the first one
c = np.hstack((a, b)))
print(c)
# output is
# [[1, 4],
#  [2, 5],
#  [3, 6]]

Example 3: np.vstack python

import numpy as np
a = np.array([1, 2, 3])
b = np.array([2, 3, 4])
np.vstack((a,b))