Integer random with integers() in NumPy

Introduction

We use integers() to get random whole numbers easily for simulations or testing.

When you want to simulate rolling dice in a game.

When you need random IDs for test data.

When you want to pick random indexes from a list.

When you want to generate random counts or quantities.

When you want to create random samples of integers for experiments.

Syntax

NumPy

numpy.random.Generator.integers(low, high=None, size=None, dtype=int, endpoint=False)

low is the smallest integer you want.

high is one more than the largest integer you want (unless endpoint=True).

Examples

Random integer from 1 to 6 (like a dice roll).

NumPy

rng.integers(1, 7)

Array of 5 random integers from 0 to 9.

NumPy

rng.integers(0, 10, size=5)

Random integer from 1 to 5 including 5.

NumPy

rng.integers(1, 5, endpoint=True)

Sample Program

This code shows how to get random integers using integers(). It creates a random number generator, then gets one dice roll, an array of 5 random numbers, and one number including the endpoint.

NumPy

import numpy as np

rng = np.random.default_rng()

# Get one random integer from 1 to 6
single_roll = rng.integers(1, 7)

# Get 5 random integers from 0 to 9
random_array = rng.integers(0, 10, size=5)

# Get one random integer from 1 to 5 including 5
inclusive_roll = rng.integers(1, 5, endpoint=True)

print(f"Single dice roll (1-6): {single_roll}")
print(f"Array of 5 random integers (0-9): {random_array}")
print(f"Inclusive roll (1-5): {inclusive_roll}")

Important Notes

Use size to get multiple random numbers at once.

By default, high is exclusive, so numbers go up to high - 1.

Set endpoint=True to include the high value.

Summary

integers() gives random whole numbers in a range.

You can get single numbers or arrays of numbers.

Remember the high value is usually not included unless you say so.