Automate The Boring Stuff With Python is an incredible book, and course by Al Sweigart to learn Python coding and computer science for the everyday person. With its straightforward learning approach, and succinct program examples and explanations, it’s many hobbyists’ go-to book for Python.
This article breaks down my personal solutions to the practice projects outlined at the end of most chapters. As I continue to learn Python and generally computer science, I enjoy seeing how others solve coding problems.
All practice projects can be found via this GitHub Repo, feel free to clone it and/or use it however you like, note, please read the disclaimer before doing so below. Also see the cloned Replit, to use the programs use the Console with the command format of python folder/file.py.
Disclaimer, this is for version 2 of the book, code is written of my own doing, any assistance will be mentioned or linked. Highly recommended you solve practice projects yourself before seeing other’s code, don’t rob yourself of any learning opportunities. I do not claim to be a professional, please share any suggestions or feedback to improve my code or this article.
Lists
Comma Code
The first practice project comes in chapter 4 which involves taking a list and printing out the items as a new string. This can be solved using two variables, a for loop and indexing. The tricky part is solving how to print the items but to do something different on the last item.
The program takes the list, loops through it and adds each item to a string.
To define a for loop up until but not including the last item in the list, you can use a negative index [:-1]. This way each item can be added to the new string as intended, but the last item can be added with the 'and '.
Note, that I’ve used format (f) strings in my example below.
def main(): print(makestring(['apples', 'bananas', 'tofu', 'cats']))
def makestring(l):
s = '' # Define blank new string
for i in l[:-1]: s += f'{i}, ' # Print out each item in the list as a new string, except the last item
s += f'and {l[-1]}' # Print out last item with 'and '
return s
if __name__ == '__main__': main()
Coin Flip Streaks
Alright, next up is finding streaks within random coin tosses, this was a bit of a tricky practice project, but a really good one. To map out the program, I used pseudo code, this helped me get a better idea of the steps involved. Simply, the program will toss a coin a certain number of times, store each toss as an item in a list, and then loop through the items to find a streak.
I broke this program into two functions, 1) flip, and 2) streak. This keeps things organised, makes coding easier and abstracts away elements within the program.
So, the flip function is solely responsible for taking a number from the user, flipping the coin based on that number and storing the results in a list.
Then, the streak function takes that list to find the streaks, this was the most difficult part of the practice project. I found this Reddit post via r/learnpython which made things more simple for me. The problem was tracking if a streak was found or not, since we can use a for loop we know the current item. With that and indexing, we can figure out if we have a streak.
So, inside a for loop, using an if condition to match the current item to the last if that matches then a streak counter increases. This way, every item must be the same as the last to count up, once that counts up to a certain number, in this case, six, then we have a streak.
A separate variable called streaks increases and that is the final output that feeds back to the user.
from random import randint
def main(): print('Streaks: ' + str(flip(input('Number of flips: ')))) # Prints output to terminal
def flip(number):
coin_list = [] # Create empty list to store coin tosses
for i in range(int(number)): # Loop thourgh number provided by user
coin = randint(0,1) # Each loop give random 0 or 1
coin_list.append(coin) # Add random 0 or 1 to list
return streak(coin_list) # Pass list through streak function
def streak(l):
streaks, streak = 0, 0 # Create counters for a single streak, and the overal amount of streaks
# Loop through the list of coin tosses
for i in range(1, len(l)):
if l[i] == l[i-1]: # Check if the current toss is equal to the last toss
streak += 1 # If so, count up on the streak
else: streak = 0 # Otherwise, set the streak back
if streak == 6: # Now check for a total of six in a row
streaks += 1 # Add to the overal amount of streaks
streak = 0 # Reset the streak counter back to nothing
return streaks
if __name__ == '__main__': main()
Character Picture Grid
This practice project took a lot of internal visual imagery to work for me, it reinforced the for loop which was great. As per the hints, you can use a for loop inside a for loop it feels a bit inception-like at first.
What helped me, was referring back to the list stored within grid, the first for loop is iterating over each list of items, and the second is iterating over each item within the lists. I know, it’s a bit confusing, but the more you go over it, the more it makes sense.
To help break this down further, I used the names rows and columns instead of the x and y axis, that just helped me. The draw function starts with declaring these variables and stores integer values, these match the item I want to first print out.
Within the second for loop we want to print out using indexing, this way we can print exactly the item we want.
Since we’re starting out in row position 8, and column position 0, meaning the first column and the last row item. Then we go up row by row within the second for loop, then column by column within the first for loop. Once the program reaches column 5, then it breaks out of the loop, and the character picture grid has been rotated and printed out to the terminal.
grid = [['.', '.', '.', '.', '.', '.'],
['.', 'O', 'O', '.', '.', '.'],
['O', 'O', 'O', 'O', '.', '.'],
['O', 'O', 'O', 'O', 'O', '.'],
['.', 'O', 'O', 'O', 'O', 'O'],
['O', 'O', 'O', 'O', 'O', '.'],
['O', 'O', 'O', 'O', '.', '.'],
['.', 'O', 'O', '.', '.', '.'],
['.', '.', '.', '.', '.', '.']]
def main(): draw(grid)
def draw(l):
row, column = 8, 0 # Start in bottom left of grid list
for i in l: # Loop through lists in grid
for j in l: # Loop through items in each list
print(l[row][column], end='') # Print out as per starting point
row -= 1 # Reverse up the column, results in row output
if column < 5: # Go until row 6 (0-5)
row = 8 # Reset column back to the bottom or last
column += 1 # Move up a row to being new row
print('') # Print new line
else: break # Once greater than 6th row, break and exit out
if __name__ == '__main__': main()
Dictionaries and Structuring Data
(Coming Soon)
This is day 50 of #100DaysOfHacking on my Hackers Learning Path. Subscribe for CyberSec updates or read more, happy hacking/coding/learning.