python-exercises

In this repository I will put my exercises from "CS50's Introduction to Programming with Python"

Problem Set 0

• Indoor Voice WRITING IN ALL CAPS IS LIKE YELLING. Best to use your “indoor voice” sometimes, writing entirely in lowercase. In a file called indoor.py, implement a program in Python that prompts the user for input and then outputs that same input in lowercase. Punctuation and whitespace should be outputted unchanged.

• Playback Speed Some people have a habit of lecturing speaking rather quickly, and it’d be nice to slow them down. In a file called playback.py, implement a program that prompts the user for input and then outputs that same input, replacing each space with ... (three periods).

• Making Faces Before there were emoji, there were emoticons, whereby text like :) was a happy face and text like :( was a sad face. In a file called faces.py, implement a function convert that accepts a str as input and returns that same input with any :) converted to 🙂 and any :( converted to 🙁. Then implement a main function that prompts the user, calls convert, and prints the result. Be sure to call main at the bottom of your file.

• Einstein Implement the mass–energy equivalence formula E = mc². In a file called einstein.py, prompt the user for mass as an integer (in kilograms) and output the equivalent number of Joules as an integer, assuming the speed of light is 300000000 m/s.

• Tip Calculator In the United States, it’s customary to leave a tip for your server after dining, typically 15% or more of your meal’s cost. In a file called tip.py, implement a program that prompts the user for the cost of a meal as a number and outputs how much to tip (15% of the cost), formatted to two decimal places.

Problem Set 1

• Deep Thought In deep.py, prompt the user for the answer to the Great Question of Life, the Universe and Everything, outputting Yes if the input is 42 or (case-insensitively) forty-two or forty two; otherwise output No.

• Home Federal Savings Bank In bank.py, prompt the user for a greeting. If it starts with “hello”, output $0; if it starts with “h” (but not “hello”), output $20; otherwise output $100. Ignore leading whitespace and treat input case-insensitively.

• File Extensions In extensions.py, prompt the user for a filename and output its media type based on its extension (.gif, .jpg, .jpeg, .png, .pdf, .txt, .zip); otherwise output application/octet-stream.

• Math Interpreter In interpreter.py, prompt the user for an expression formatted as x y z (e.g., 1 + 1) and output the result as a float with one decimal place. Assume x and z are integers and y is one of +, -, *, /.

• Meal Time In meal.py, implement convert(time: str) -> float that converts a 24-hour time (e.g., 7:30) to hours as a float (e.g., 7.5). In main, prompt for a time and output breakfast time if between 7:00–8:00, lunch time if between 12:00–13:00, dinner time if between 18:00–19:00; otherwise output nothing.

Problem Set 2

• camelCase In camel.py, prompt the user for a variable name in camelCase and output the corresponding snake_case version.

• Coke Machine In coke.py, simulate a machine that sells a Coke for 50 cents. Prompt the user to insert coins (25, 10, or 5 cents) until at least 50 cents is inserted; then output the change owed.

• Just setting up my twttr In twttr.py, prompt the user for text and output it with all vowels (A, E, I, O, U) removed (case-insensitively).

• Vanity Plates In plates.py, prompt the user for a vanity plate and output Valid if it:

  1. Starts with at least two letters,
  2. Has 2–6 characters,
  3. Has numbers only at the end (and the first number is not 0),
  4. Contains no periods, spaces, or punctuation; otherwise output Invalid.

• Nutrition Facts In nutrition.py, prompt the user for a fruit (case-insensitively) and output the number of calories in one portion, per the FDA’s poster for the 20 most frequently consumed raw fruits.

Problem Set 3

• Fuel Gauge In fuel.py, prompt the user for a fraction X/Y. If X and Y are integers, 0 < X ≤ Y, and Y ≠ 0, output the tank’s fullness as a percentage (rounded to the nearest integer). If the result is ≤ 1%, output E; if ≥ 99%, output F. Otherwise, prompt again (handling ValueError and ZeroDivisionError).

• Taqueria In taqueria.py, given a dict menu of items to prices, prompt the user for items (case-insensitive) until Control‑D. After each valid item, output the total cost so far, formatted as $x.xx.

• Grocery List In grocery.py, prompt the user for grocery items until Control‑D. Then print each item in uppercase, sorted alphabetically, prefixed by the count of how many times it was entered (case-insensitive).

• Outdated In outdated.py, prompt the user for a date in M/D/YYYY or Month D, YYYY format (Month as full name). If valid (assuming all months ≤ 31 days), output it in ISO 8601 YYYY-MM-DD format; otherwise prompt again.

Problem Set 4

• Emojize ecause emoji aren’t quite as easy to type as text, at least on laptops and desktops, some programs support “codes,” whereby you can type, for instance, :thumbs_up:, which will be automatically converted to 👍. Some programs additionally support aliases, whereby you can more succinctly type, for instance, 👍, which will also be automatically converted to 👍. See carpedm20.github.io/emoji/all.html?enableList=enable_list_alias for a list of codes with aliases. In a file called emojize.py, implement a program that prompts the user for a str in English and then outputs the “emojized” version of that str, converting any codes (or aliases) therein to their corresponding emoji.

• Frank, Ian and Glen’s Letters Among the fonts supported by FIGlet are those at figlet.org/examples.html. FIGlet has since been ported to Python as a module called pyfiglet. In a file called figlet.py, implement a program that:

  • Expects zero or two command-line arguments: Zero if the user would like to output text in a random font. Two if the user would like to output text in a specific font, in which case the first of the two should be -f or --font, and the second of the two should be the name of the font.

  Prompts the user for a str of text. Outputs that text in the desired font. If the user provides two command-line arguments and the first is not -f or --font or the second is not the name of a font, the program should exit via sys.exit with an error message.

• Adieu, Adieu In The Sound of Music, there’s a song sung largely in English, So Long, Farewell, with these lyrics, wherein “adieu” means “goodbye” in French:

  Adieu, adieu, to yieu and yieu and yieu Of course, the line isn’t grammatically correct, since it would typically be written (with an Oxford comma) as:

  Adieu, adieu, to yieu, yieu, and yieu To be fair, “yieu” isn’t even a word; it just rhymes with “you”! In a file called adieu.py, implement a program that prompts the user for names, one per line, until the user inputs control-d. Assume that the user will input at least one name. Then bid adieu to those names, separating two names with one and, three names with two commas and one and, and names with commas and one and, as in the below:

  • Adieu, adieu, to Liesl
  • Adieu, adieu, to Liesl and Friedrich
  • Adieu, adieu, to Liesl, Friedrich, and Louisa
  • Adieu, adieu, to Liesl, Friedrich, Louisa, and Kurt
  • Adieu, adieu, to Liesl, Friedrich, Louisa, Kurt, and Brigitta
  • Adieu, adieu, to Liesl, Friedrich, Louisa, Kurt, Brigitta, and Marta
  • Adieu, adieu, to Liesl, Friedrich, Louisa, Kurt, Brigitta, Marta, and Gretl`

• Guessing Game I’m thinking of a number between 1 and 100… What is it? It’s 50! But what if it were more random? In a file called game.py, implement a program that: Prompts the user for a level, . If the user does not input a positive integer, the program should prompt again. Randomly generates an integer between 1 and , inclusive, using the random module. Prompts the user to guess that integer. If the guess is not a positive integer, the program should prompt the user again.

  • If the guess is smaller than that integer, the program should output Too small! and prompt the user again.
  • If the guess is larger than that integer, the program should output Too large! and prompt the user again.
  • If the guess is the same as that integer, the program should output Just right! and exit.