Lesson 15 - Python Standard Libraries

Learning Objective

• Import and use two of Python’s standard library modules — random for unpredictability and datetime for working with dates and times — without installing anything extra.

Introduction

Python ships with a huge standard library — modules you can import immediately, with no pip install needed.

This lesson covers two you’ll reach for constantly:

• random, for anything involving chance or unpredictability.
• datetime, for reading and formatting the current date and time.

Code

import random
from datetime import datetime
 
# random
dice_roll = random.randint(1, 6)
print(f"Dice roll: {dice_roll}")
 
colors = ["red", "green", "blue", "yellow"]
chosen_color = random.choice(colors)
print(f"Chosen color: {chosen_color}")
 
shuffled = colors.copy()
random.shuffle(shuffled)
print(f"Shuffled: {shuffled}")
 
# datetime
now = datetime.now()
print(f"Current time: {now}")
print(f"Formatted: {now.strftime('%Y-%m-%d %H:%M:%S')}")
print(f"Day of week: {now.strftime('%A')}")

Expected Output

Dice roll: 4
Chosen color: blue
Shuffled: ['yellow', 'red', 'blue', 'green']
Current time: 2026-07-22 14:03:11.842013
Formatted: 2026-07-22 14:03:11
Day of week: Wednesday

🔧 Under the Hood

random.seed(42)

Student Challenge

Challenge 1 — Python only

Simulate rolling two dice 10,000 times and count how often each total comes up.

• Roll two 6-sided dice (random.randint(1, 6)) 10,000 times.
• Sum their values and store the count of each total in a dictionary.
• Print the totals sorted from 2 to 12 along with their frequencies.

import random
 
roll_counts = {}
 
for _ in range(10000):
    total = random.randint(1, 6) + random.randint(1, 6)
    roll_counts[total] = roll_counts.get(total, 0) + 1
 
for total in sorted(roll_counts):
    print(f"{total}: {roll_counts[total]} times")

Challenge 2 — Robot

Have your BonicBot perform a randomized sequence of moves, with each one timestamped.

• Create a list of moves MOVES = ["forward", "turn_left", "turn_right", "backward"].
• Loop 4 times, pick a random move using random.choice(MOVES), print the current timestamp formatted as %H:%M:%S, and execute the corresponding movement.
• Make sure the if/elif chain covers every move in MOVES, including "backward".

Full movement methods are in the Python SDK reference.

import random
from datetime import datetime
from bonicbot_bridge import BonicBot
 
MOVES = ["forward", "turn_left", "turn_right", "backward"]
 
with BonicBot(host='192.168.0.188') as bot:
    for step in range(4):
        move = random.choice(MOVES)
        timestamp = datetime.now().strftime('%H:%M:%S')
        print(f"[{timestamp}] Step {step}: {move}")
 
        if move == "forward":
            bot.move_forward(speed=0.2, duration=1.0)
        elif move == "turn_left":
            bot.turn_left(speed=0.5, duration=1.0)
        elif move == "turn_right":
            bot.turn_right(speed=0.5, duration=1.0)
        elif move == "backward":
            bot.move_backward(speed=0.2, duration=1.0)
 
    bot.stop()

Library Quick Reference

Reflection Question