numpy.hstack() and numpy.vstack() in Python with Example

What is hstack?

With hstack you can appened data horizontally. This is a very convinient function in Numpy. Lets study it with an example:

## Horitzontal Stack
import numpy as np
f = np.array([1,2,3])
g = np.array([4,5,6])

print('Horizontal Append:', np.hstack((f, g)))

Output:

Horizontal Append: [1 2 3 4 5 6]

What is vstack?

With vstack you can appened data vertically. Lets study it with an example:

## Vertical Stack
import numpy as np
f = np.array([1,2,3])
g = np.array([4,5,6])

print('Vertical Append:', np.vstack((f, g)))

Output:

Vertical Append: [[1 2 3]
 [4 5 6]]

Generate Random Numbers

To generate random numbers for Gaussian distribution use

numpy.random.normal(loc, scale, size)

Here

• Loc: the mean. The center of distribution
• scale: standard deviation.
• Size: number of returns

## Generate random nmber from normal distribution
normal_array = np.random.normal(5, 0.5, 10)
print(normal_array)			
[5.56171852 4.84233558 4.65392767 4.946659   4.85165567 5.61211317 4.46704244 5.22675736 4.49888936 4.68731125]			

If plotted the distribution will be similar to following plot

Summary

Below, a summary of the essential functions used with NumPy