Appendix 2: Random Integer Generator

Watch demo video

"A random number generator, generates a sequence of numbers or symbols that cannot be reasonably predicted better than by a random chance." Wikipedia

To randomly generate $n$ integers between $a$ and $b$, inclusive, use the following function from the numpy library. Here $n,a$ and $b$ are integers.

import numpy as np  
np.random.randint(a, b+1, size=n)

The above code returns an array of $n$ random integers from $a$ to $b+1$, inclusive. Notice that every time you run the program, it will generate different sets of numbers. To create the same set of random numbers you can add the line np.random.seed(123).

Example: Write a program to randomly select one integer between 1 and 10.

1. Click + Code
2. Type import numpy as np
3. Type np.random.randint(1,10+1,size=1)
4. Click play button

import numpy as np
np.random.randint(1,10+1,size=1) 

array([5])

Interpretation: The number 5 is randomly selected from all integers between 1 and 10. If you run this program again, it will, most likely, generate a different result.