Python

100DaysOfCode

100 Days of Python, Projects 23-31 #100DaysofCode

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In case anyone is keeping track (which they are not), you might notice that one, I’ve not been posting these posts in “real time”.  I’ve been writing them later, after the fact.  I kind of hope to change that.  Also, I started on September 12th, and my last post was on September 28th, which is 16 days, though the last post went through Day 22.  I’m actually moving faster than “100 Days” on my “100 Days of Code”.

This is intentional, I want to do Advent of Code again this year, starting December 1st. So I want to hopefully finish this up before December, so I am not overlapping these two daily level coding projects.  I just, don’t have the time to do both.  Based on my calculations, I need to get 18 projects ahead to end on November 30th.

Anyway, this round I want to wrap up the “Intermediate” level projects.  This one may be a bit boring, just because it is a lot more “Basic Data Analysis” projects than “Cool Retro Game remakes”.

Day 23 – Turtle Crossing or Crossey Turtle

I was a little disappointed because the description sounded like this was going to be a “remake” of Frogger, only with Turtles.  Instead it’s a remake-ish, of Crossey Road.  Which is slightly less exciting.  I feel like I could probably make my own Frogger, and I will probably put that on a ToDo list somewhere to forget about because all my ToDo lists are 1000 items long….

Anyway, the job is to get the turtle across by avoiding the cars, which randomly spawn on one side of the screen.  Each time the turtle makes it, the cars start moving slightly faster.  It was an interesting project to develop, and like Snake, I cleaned it up a bit from the instructor’s code by aligning the cars and turtle to lines.  The main this this does it helps to remove the ugly overlap with a pure random spawn.  I considered adding some code to stop them from spawning on top of each other in the same line but decided I didn’t care enough to bother.  

The trickiest part of this was adjusting the delays and spawn timer so things felt right.  With a spawn timer too low, then cars were just pouring out.  With it too high then the road is just wide open.  Another issue I had briefly, when the cars would speed up, only the currently on screen cars would speed up, everything new would still run slow.

In general I don’t really care for this game, primarily I think because the game actually gets easier the faster the cars get because the gaps become huge and easy to pass through.  It could be adjusted a bit probably to spawn more cars at higher speeds which may fix this.

Day 24 – Improved Snake Game and Mail Merge

Today’s lesson had to do with file I/O.  I’m actually already pretty familiar with this, a lot of the scripts I have written in my free time take a file in, manipulate the data in some way, and spit a file out.  

Step one was to modify the Snake Game to have a persistent high score written to a file.  Which was neat.

The second was a simple Mail Merge exercise.  Take in a letter, take in a list of names, output a series of letters with the names inserted.

Day 25 – US State naming Game

The exercise today was an introduction to Pandas, which is a tool that makes working with large data sets much easier.  In the first round of practice, we pull data from a large csv of Squirrel Data and count Squirrel Colors from here: https://data.cityofnewyork.us/Environment/2018-Central-Park-Squirrel-Census-Squirrel-Data/vfnx-vebw which was silly and fun.

The second was a little learning game where the player names states of the United States.  Each correct guess shows on the map.  When you type “Exit” you get a file back of which states were missed.  One of the interesting things here was adding a background image to the Turtle Screen.  I also tried to build it in a way that it would be easy to say, swap out the background image and data set for European Countries, or anything similar.

On a total side note, I got all 50 states on my first try.  I am pretty sure I know all the capitols still as well.

Day 26 – List and Dictionary Comprehension and NATO Alphabet Translator

Probably one of the quickest programming days but longer lessons page with several simple exercises.  It also felt like one of the more “necesary in the long run” lessons.  Basically, the whole lesson was about better ways to iterate through data.  Single line codes like “list = [item for item in other_list]”.

The end project was very short, pull in a CSV of NATO Phonetics using Pandas, then one line iterate it into a dictionary.  Ask for a user input, loop through the user input to make a list of words, output the list.

Day 27 – Miles to Kilometers Conversion Project and TKinter

So on the surface, a Miles to Kilometers converter isn’t that exciting.  In fact, it’s a straight forward multiplication/division that even the most beginner level coder could whip up.  The point of this lesson was more of an introduction to TKinter.  

The end result is a little window based converter, that in my case, goes both ways, so you can do Miles to KM or KM to Miles, which is probably boring but wasn’t part of the requirement for the project.

Day 28 – Pomodoro Timer

The object of this lesson was to build a Pomodoro Method Timer.  I don’t super follow “productivity” methods but I guess the Pomodoro Method is to use a timer, work for a period, take a short break, repeat this pattern a few times, then take a longer break.  I don’t know if these times are set in stone, but for the project we used 25 minutes of work, 5 minutes of break, repeated 3 times, and then 20 minutes of long break.

The actual lesson here is how to create a TKinter window that is “constantly running”.  While able to take some input, and manipulating various bits of the UI.  It counts down a timer, it adds check marks every round, it had a start and reset button.  

This one was actually pretty tricky, and I kept ending up with essentially several layered running timers because I was using the window.after function improperly at first.  Otherwise it’s just a loop that runs through some conditionals to see where it’s at in the loop.  I did manage to do like 90% before watching the videos, but it took me an extra session of code work to puzzle it out.  The one bit I wasn’t sure on was how to make the Reset button actually top the timer loop, which wasn’t complex, but I did have to get that one from the class.

Day 29 – Password Manager Part 1

So, I really liked this project, and I need to find out how to make exe files out of these pieces of code.  I actually would definitely use this project regularly, especially after adding some additional features, which may in fact come in tomorrow’s part 2.  This was also another project that I essentially completely built before actually watching the lessons.  Which I suppose means the previous lessons on how to use TKinter worked well.  I will say, the most annoying part of TKInter is just how finickey the positioning can get,  The instructor likes using Grid() to place but personally, I think I like using Place(), but the problem is, I could get caught up tweaking Place() for hours.

This project so far has combined several previous projects, from the Password Generator, to using TKinter, to writing output files.  I suspect tomorrow will add in even more with Reading Files, and working with “organized data” in the process.  I could also see using Ciphers to actually encrypt the output data file to something that’s not readable without a master password.

My favorite part was revisiting the “Password Generator” code created back on Day 5.  In addition aot simplifying it with some list comprehension, I also converted it to be an Object Oriented Class, that could be imported and called. Not super difficult but I still felt pretty proud of that one. It doesn’t really add a lot of benefit, but it was more just an exercise for my own ability.  I also made it easy to change the default email address by putting it in a separate config style file that I may work with more later.

Day 30 – Password Manager Part 2

Most of this day’s lesson was using error handling, specifically, “try:”, “except:”, “else:” and “finally:”.  I kind of figured there was a better way of handling “random errors” than painstakingly considering every option, but I’ve never really had a need to look into it too super deeply.  Usually for error handling, I’d just stick an “if” into a loop, and if the “if” fails, it just keeps looping until the input is good.  

I did this a lot early on, on my own accord, for many of the text inputs.  I would make an array of “valid entries”, often something like:

valid = [“yes”, “y”, “no”, “n”]

while answer not in valid:

    answer = inout(“Yes or no?: ).lower()

Which honestly is probably still plenty valid for small choice selections.

I was a bit disappointed that the end result didn’t even make a token attempt to encode the output data, storing passwords in plain text is a really really really really really really bad idea.  Oh well, future project.  

All in all, this is definitely the most complex project so far, and it’s possible the most complex single project I’ve done ever code wise.  I’ve done some elaborate PHP/HTML/CSS web stuff, but those were always more, ongoing projects with sub-projects tacked on to them.

Day 31 – Flashcard App

Another one that I definitely will use once I make it work in a stand alone fashion in the future.  This app was quite a bit simpler than the Password Manager but I’ve found that so far, at the end of each section, there has been a complex capstone project, then a few simpler ones.  The bigger purpose of this project was learning to manipulate JSON and CSV data better, in addition to making a simple GUI.  

This app reads some data in, in this case, language words, but it could be any set of data.  Then it shows the foreign word, for three seconds, before showing the English word.  If you guessed it correctly, you hit the green box, it not, hit the X.  It’s kind of an honor system thing, but if you are trying to learn a language, why would you cheat yourself like that.

It also removes “learned words” from the pool of possible cards, permanently.  Well, or until you reset it by deleting the save files.

I’ve written a few times about my goal to learn some languages besides English by 2030.  I’ve gotten alright at Spanish, and I’ve been working on Norwegian.  The class provided a word bank for French but also explained how to make your own word bank, which I did.  Making a new word bank was not required, but I know absolutely zero French, and it was hard to tell if the cards were accurate.  So I built a Norwegian Word Bank, and will definitely build a Spanish one.  The only problem is, I went with the “Top 10,000 words”, and you only really need the “Top 2-3000 words” to start grasping the language.  So my custom word bank helped, but not as much as it could have, because I started getting some really lesser used words.  It’s easy enough to trim it off though, I can just open the data file and delete the bottom 9,000 lines.

And so this wraps up the “Intermediate” lessons.  The next session is “Intermediate+”.  Based on the daily topic headers, it looks like this next section is going to delve way deeper into using APIs to gather and manipulate web services, which should be a lot of fun.  I’m definitely learning more and I plan to revisit some of my own personal projects to make them much better once I’ve finished with the course.  A lot of my old data manipulation involved lists and a lot of if/else statements inside for loops.  Which is messy, and probably slow.  A lot of the new tools I’ve learned will really help.

100DaysOfCode

100 Days of Python, Projects 15-22 #100DaysofCode

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So, the first set of projects for #100DaysOfCode were all fairly simple.  Basic Text based programs that run in a terminal and run through simple loops.  The Intermediate Section starting on day 15 of the course is were things started to get quite a bit more interesting, though the basic code isn’t really all that complex yet.

There are two main topics covered during the Intermediate portion of the course, creating GUI interfaces with Turtle Graphics, and some introductory data analysis.  These two topics don’t particularly overlap, but both seem to be the primary focus here.  I’m rather enjoying the use of graphics over just terminal applications myself, though int he long run, handling CSV and other data feeds will probably be a lot more useful.

In the interest of brevity, I’m going to split the intermediate section up into a couple of posts.  I expect this to become more common as the projects become more complex and frankly, by the end, each project may even get it’s own post.

Anyway, on with the projects…  As before, all of the code is stored in this GitHub Repository.

Project 15 – The Coffee Machine Project

The actual focus for Day 15 was to set up PyCharm, and get away from using Replit for the code projects.  I’d already been using VS Code half the time anyway, but I switched over to PyCharm on this day.  A few reasons, one, it’s what the course is using, so it’s easier to follow if needed, two, it was easier to import libraries into projects than with VS Code.

The Coffee Machine project is a simple project that takes an order for a coffee, takes some coins, then spits out change and a coffee.  It doesn’t ACTUALLY do any of this physically, but if it did, that would be super impressive, manifesting physical objects with a laptop.

Project 16 – The Coffee Machine Project

Nope, you aren’t reading that wrong, the next day was the same project.  The difference was, Day 16 was also an introduction to Object Oriented Programming.  So for this project the students get some files with pre-made functions in them, and we build the same Coffee machine using these functions in an Object Oriented Programming way.

This was the first time I’ve actually learned something new in this course.  All of my code before has essentially just been “one file”.  The concept of breaking things into files and classes that do specific tasks is pretty neat, and I’ve gotten pretty good at it.  That said, I can also see where it’s still a good idea fo make a judgement of if something should be it’s own class or just be part of the base program.

There was also a brief introduction to using Pretty Tables to display data and Turtle Graphics, though the final program didn’t use any graphics.

Project 17 – Quiz Game Project

Another Object Oriented project, though instead, we make everything this time.  The questions were provided, but they are set up in a way that it’s simple to replace them with new questions from Open Trivia.  This also really helps push how useful it can be to break a program apart like this, across files.  The questions aren’t a class, they are just a dictionary you import, but they can easily be quickly replaced and the same code will run on any set of questions.

Project 18 – Hirst Painting Project

This one was a more in depth and proper look at Turtle Graphics.  Turtle is Python’s built in method for creating graphics and windows.  I’m sure there are probably others out there, but this works pretty well for a simple interface.  

The first practice was making the Turtle do some things, one of which was a pretty neat Spirograph drawer, which I may revisit in the future to make it useful.  Maybe have a pop up for how large or how many spirals to make.

The Hirst Painting project was inspired by the artist Damien Hirst, who apparently once sold some paintings consisting only of regularly placed dots.  The program takes an input image, extracts a color pallet from it, then creates a similar dot based image.  The instructor used a Hirst painting as the input, I opted to use the cover of the CHVRCHES album Every Open Eye.  It’s a pretty neat result.  It’s another that could be made more robust by prompting for an input image, how many colors to extract and how many dots to draw.

Project 19 – Turtle Racing and Etch-A-Sketch

This day was essentially two projects.  One was a simple Etch-A-Sketch style drawing program, that served as an introduction to actually controlling the Turtle with keyboard inputs.  

The second I particularly enjoyed, though it wasn’t a very complex game.  The second was Turtle Racing.  The purpose was to demonstrate how you can reuse classes to manage several variables of the same class type.  It spawns 6 turtles, you guess which will win, then they race across the screen to the finish line.

Now why is this exciting?  Waaaaaay back in the year 2000, I had a semester to kill between Community College and University, so I took a Computer Science 101 course where I learned some C++ programming.  One of the projects for that class, was a Horse Racing game, that is essentially the same concept.   The Horse Racing Game can be found here, and there is even an exe that lets you play it.  https://github.com/RamenJunkie/C_and_CPP_Code_Snippets/tree/main/CPP%20Code/Horse%20Race

Project 20 and 21 – Snake Game

The first multi day project of the course, well, ok, the Coffee Machine was SORT OF Multi Day, but not really.  This project recreates the classic game Snake.  I’m sure it existed before, but it was popularized by being included on Nokia Phones back in the 90s and early 2000s.

You control the snake, eating food to get longer, and avoiding running into the wall or yourself.  I am pretty happy with the result other than the controls feel like they could be a bit more responsive.

One thing I am proud of with the Snake Game though, I noticed in the instructor’s examples, she was constantly missing the food just barely. In her code, the food just randomly spawns. I changed the code a bit so the food always spawns on the same grid the Snake runs on, which makes it way more reliable to pick up. I also added a border, but I’m less satisfied with that because it seems Python renders things a little funny and slightly off center. I suspect that Python Turtle things are drawn from one corner of the coordinates, and not centered on the coordinates.  

Project 22 – Pong

I’m rather proud of this one, so we’ll cap this round of write ups off with it.  the Day 22 project was to recreate Pong, often cited as the “first video game”.  It’s simple, two players each have a paddle on opposite sides of the screen, the ball bounces back and forth, missing the ball grants score to the other player.

This project combines quite a few things leading up to this point from creating custom classes to taking inputs, drawing graphics. Ok, so technically the Snake Game did all of this. My real win here is doing it, entirely on my own, before watching ANY of the class videos for the day. (Ok, I may have watched the intro just to get the scope of the project, sometimes the instructor throws some curve-ball concepts in.)

Now, don’t get me wrong, in most cases, I do the coding on my own, based on what’s presented, but I usually follow along with the class and do each bit as it’s asked.  I also will occasionally “correct” my code to better align with what’s presented, not because I think my methods are wrong, but more because the instructor may later introduce a concept that needs the code to be set up a particular way.

For Pong, I did it all.  I am plenty familiar with how Pong works, I viewed the 2 minute “What we are making” first video to get the scope, then went off on my own.  And it all worked out.  Getting the ball bounce just right was the trickiest part, mostly because I started seriously over thinking the physics of it.

It really helps that I already know how to code, and have a “programmer mindset” on how to step through things.

  • Make a Paddle Class
  • Spawn a Paddle
  • Make the Paddle Move
  • Keep the Paddle within the screen constraints.
  • Spawn a second Paddle
  • Make the second paddle move with different keys
  • Draw the net
  • Make a ball
  • Make the ball move
  • Make the ball bounce withing the screen
  • Make the score board
  • Make the Scoreboard increment when the ball bounces off of left and right
  • Make the ball re-spawn when it hits left or right instead of bounce
  • Make the ball bounce off of a paddle

That’s pretty much it, the steps to making Pong.   Most of them are super easy.  I even added an additional class that would draw a “net” across the center of the screen that wasn’t required (not that anyone is grading this code).

The point was, I did it all, then watched the videos, just to see if there was any better way to do some of the things I had done.  Felt like a pretty cool accomplishment.

100DaysOfCode

100 Days of Python, Projects 1-14 #100DaysofCode

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I’ve mentioned before about the concept of “always learning”.    One of those thing is coding.  I’d like to think I’m actually pretty good at basic to intermediate level coding, though I am certainly not an expert.  I kind of feel like I am at a point where I would definitely like to “level up” my ability a bit.  So I’ve been working on the #100DaysOfCode Challenge, though a course on Udemy.  Specifically, 100 days of Python, and specifically, this course.

I’ve also been using this as an good excuse to sharpen up my Github skills a bit, so you can follow my progress along in my Github Repository.  I also figure I could talk about about some of my though processes and flow here as well, though some of the projects are very simple, so there may not be a lot to say about them specifically.  Especially since, frankly, I am already beyond the “Beginner Level” of this course.

I thought about making a post for each module, but that’s kind of overkill as well, so instead I’ll just break it up a bit across maybe the skill levels, or whenever I feel like it.

Project 1 – Band Name Generator

This one is pretty basic, and basically, the same sort of thing you see on Facebook trying to steal your information.  I promise I’m not trying to steal your data though.  It takes some simple inputs, the city you were born in, your pet’s name, and outputs them as a combination for a “Band Name”.  You can really put anything you want into these fields and it will just combine them.  Maybe a fun alternative would be to use the letters of the words entered, to pull a different word from a list or something.  

Project 2 – Tip Calculator

This one is mildly more complicated than the Band Name Calculator, but it is still just input fields, but this time, with MATH!  You enter the total bill, how much to tip, how many people ate, and it splits the bill among the various people evenly.  Be sure you order the steak dinner, so your salad eating friends can foot part of the bill for your expensive steak.

Project 3 – Treasure Island Game

I really enjoyed this one, maybe a little TOO much.  The core project is just practice on “if, elif, else” statements.  You build a little “choose your own adventure” game.  Like a very simple Zork Game.  I kind of just kept getting goofier and goofier with the descriptions though.  I guess that’s the “writer” part of my personality or something.

Project 4 – Rock Paper Scissors Game

Pretty straight forward, and mostly a practice for random numbers.  A rock paper scissors game.  One part I like about this game though it that it introduces the idea of using ascii graphics.  I mean, the core idea is simple, but in all the various online coding classes I have done, none have done this sort of thing.  It really helps these little projects feel way less mundane.

Project 5 – Password Generator

More random number practice, this one actually is probably the most actually useful project so far.  You enter how many letters, numbers, and symbols you want for a password and well, it generates it, randomly.  Especially useful because strong passwords are good to have.  Though using a random password, you probably will want a password keeper, and well, most of those include a random password generator.

Project 6 – Escaping the Maze

Project 6 was a little different, since it wasn’t strictly writing pure code, but instead was using a site called Reborg’s World.  https://www.reeborg.ca/index_en.html This site has a few puzzles where you use functions to navigate a little robot through some challenges.  It’s purpose is to help the learner get better at logic puzzles mostly.  It was interesting and I’ve made a note to go back and do the rest of the puzzles at some point.

Project 7 – Hangman Game

Hey, another game.  This one is honestly, pretty full featured, at least for what it’s supposed to be.  It’s still an ASCII based CLI game but it works like Hangman.  Guess the letters, your little man slowly gets hung.  Better save him.

Project 8 – Caesar Cypher

This round is essentially just a sort of “intro to cryptography,” that I feel like may come back around in a later lesson.   This program builds a basic Caesar Cypher.  You enter some text, pick a Cypher, then it just rotates each letter by the number of letters equal to the Cypher number.  It also lets you decode the messages.

Project 9 – Secret Auction

This one was kind of neat, though not overly complicated.  Essentially, you enter your name, place a bit, if there are more people, they do the same, then it announces who the highest bidder is.  My main frustration from this project.  It’s suggested you clear the screen between bidders.   Simple enough.  but it turns out that Python doesn’t really have a built in clear function.  The samples run on the Replit website, and you have to import a special library from Replit.  This doesn’t work in my local VS Code interpreter.  I looked into this, I could write a custom include for it, but it would only work in Windows, or Mac, or Linux, not all three.  Because it’s essentially a command specific to each OS’s respective shells.

Super annoying.

Project 10 – Calculator

This would almost be really cool, if it were actually clickable and not just something you type numbers and operators into.  Still, it’s one of my favorites I think in the end, because it introduces a really interesting and neat concept involving Dictionaries.  Specifically, you have a dictionary

operations = {
    "+": add,
    "-": sub,
    "*": mult,
    "/": div,
}

You can use the key, to assign it’s value to a variable, then call that variable, as the name of a function.  The names inside the dictionary all match the names of functions.  Really slick.  Feels like it reduces code readability quite a lot though.

Project 11 – Blackjack Game

This project was alright to do but it’s a little disappointing because it fakes the cards but just using value.  It doesn’t handle Aces properly, it doesn’t handle splits or anything.   The one mistake I made, that I fixed, originally, I had set it up so the Dealer would always “Hit” of it was below the player score.  Except the dealer wouldn’t know what cards the Player had to know the player score.

Also there is not actual betting, which could make things more interesting I suppose.

Project 12 – Number Guesser

This one almost feels a bit like a filler project, since it’s a pretty straight forward if else level project.  I will also add that the hard mode gives you 5 guesses, which feels extremely low.  The logical method is halving things, so 100 -> 50 -> 25 -> 12 -> 6, so you essentially have a 1/6 chance of getting the answer.\

Project 13 – Debugging

No actual projects on day 13, so maybe it’s not actually “100 Projects in 100 days”. except several of the days have what are two to three projects, so I am sure it makes it up somewhere.   Day 13 was revisiting 3 old projects, using different methods of debugging the code provided.

Project 14 – Higher Lower Game

This game was presented as if it’s super commonly know but I had never heard of it.  It’s almost a variation of the whole Facemash/Hot or Not Idea, but with less focus on looks.  Int he example shown from the web, it uses number of Google Results for a topic, in this version it uses number of Instagram Followers.   The user is presented with two celebrities, and they have to guess which has more Instagram Followers.

It’s all pulled from pre built data, so it’s not current follower counts.   I could see this making a return when the course gets into the Web Scraping portions.

And that’s the end of the “Beginner Section”.  The course has several sections, Beginner, Intermediate, Intermediate +, some Web training, Advanced, and Professional. Most of what I’ve done so far is not really anything new.  i could have worked most of these out.  I’ve actually been spicing them up a bit with my own bits to make things more robust, like most of the inputs have some level of input check to ake sure it’s value.  Like is it a number, or did the user enter “t” or “T” or “True” or “true”.

I’m more looking forward to the next sections as it gets into GUI style training.

Advent of Code

Advent of Code 2020 – Day 15

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Hey look, Day 15 is another one that took a super long time to calculate, though it was one of the easiest to code. It’s a fancy memory game, for Elves who apparently have computer brains. You start with a series of numbers, then the next number you say, is the difference between when the previous number was said, the last two times.

For example if you start saying this sequence, with 0,1,2,3 , the next number is 0, because 3 has only been said once, after that it’s 4, because 0 was said as the 5th number and the first number (5-1). After that it’s 0 again, because 4 has not been said before, then it’s 2, because 0 is at 7 and 5 (7-5), following that is 5, because 2 is at position 8 and 5 (8-5), and so on.

Both parts were the same problem, just with a different number of iterations, 2020 and 30,000,000. Calculating the 2020th number was quick, calculating the 30 millionth number, not so much.

Anyway, here is my code:


values = [0,8,15,2,12,1,4]

current = 0


while current < 30000000-7:
  check = values[-1]
  last = len(values) - values[::-1].index(check)
  if check in values[:last-1]:  
    temp=values[:last-1]
    temp.reverse()
    #print len(values)
    sec_last = len(values) - temp.index(check)-1
    next = last-sec_last
  else:
    next = 0
  values.append(next)
  #print next

  #print len(values)
  current+=1

print values[:-1]
print len(values)

I had some extra prints in there for the 2020, but printing everything for 30 million just slows it down. The final length print is just to verify that it’s giving me the correct iteration value. The main this this could use for clean up is to replace the while loop “-7” subtraction with subtracting a variable equal to the length of the initial values set, so that you could potentially feed it a value set that is larger or smaller.

The trickiest part here was figuring out the positions of the last two occurrences of a number, which meant counting backwards through the array of values. For the second number, I ended up using a reverse copy of the array, because I kept getting screwball answers trying to do it directly like I had for the first number. I would have liked to make it work with the more elegant solution but I didn’t have time to keep working on it.

Advent of Code

Advent of Code 2020 – Day 13

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Today’s lesson in extremely, incredibly, stupidly, inefficient methodology, is brought to you by, the letter “i” and the number “640856202464541”. Day 13 consisted of calculating bus departure times. Part 1 was stupidly simple. You have a list of buses, each bus makes a regular round trip to wherever, and the round trip always takes the same amount of minutes. At some point in the past, the buses all left at once.

Say the buses were 4, 5, and 6, each number also being the minutes for a round trip. Every 4 minutes, bus 4 returns, every 5 minutes bus 5 returns, every 6 minutes, bus 6 returns. If you are available to leave at 9 minutes, which bus leaves first. In this example, the first bus to return would be 5 (5*2=10)

Part 1 was easy, start at your departure time, check to see if any of the numbers divide into it evenly, if not, increment by one and repeat.

with open('day13data.txt') as f:
    lines = [line.rstrip() for line in f]

time = int(lines[0])
raw = lines[1].split(',')
busses= [] 

for i in raw:
  if i != 'x':
    busses.append(int(i))

print time
print busses

for x in busses:
  bus_time=x*(round((float(time)/float(x))+.5))
  wait=bus_time-time
  print "For bus "+str(x)+": "+str(bus_time)+" and you will wait: "+str(wait)+" Ans: "+str(x*wait)

The trickiest part is that the data contained non existent buses, labeled with an “x”. These are not a factor for part 1, so they just get stripped out.

Part 2 is where the pain in the ass was. For Part 2, you have to find a starting time where each bus, will leave, one minute apart, according to their offset. This includes the “missing” buses. So for the quick example I had above of 4,5,6, this time would occur at well, 4 minutes, because I made them sequential, but the next one would occur at 64,65,66 (16*4, 13*5, 11*6). This gets even more complicated when you add in the blanks, for example, 4,x,5,x,6 occurs at 68,70,72. As you spread the numbers apart and rearrange them to be non sequential, it complicates everything more.

I actually figured out the methodology pretty quickly, and wrote a working, good bit of code pretty quickly, my problem, was picking a starting point. I am sure there is some numerology methods (I am pretty sure you can do something using remainders), to calculate even an approximate starting point. In my standard of ugly code, I was just brute forcing it.

with open('day13data.txt') as f:
    lines = [line.rstrip() for line in f]

lines_array = lines[1].split(',')
times = []
counter=0
#First for sample Data Set day13datab.txt, second for real data
#multiplier=152600
multiplier=15630639084400
offsets=[]
busses=[]

for i in lines_array:
  if i != 'x':
    busses.append(i)
    offsets.append(lines_array.index(i))

#print busses
#print offsets

while (1):
  for i in offsets:
    times.append(((int(busses[0]))*multiplier)+i)

  #print times
  counter=1
  for j in busses[1:]:
    #print j
    if (times[counter]/float(j)).is_integer():
      counter+=1
    else:
      break
        
  #print times
  #print counter
  if counter == len(busses):
    break
  counter = 0
  times =[]
  multiplier+=1
  #print multiplier

print times

The problem is, this takes a very, very, very, very, very, long time. I left this code running for hours on my server and it didn’t finish, I honestly feel like it could very likely run for days, weeks, years, and never finish. The iteration on my multiplier that gives the correct set, for my data (every person has a different data set) was 15,630,639,084,501. 15 TRILLION.

So I fudged it a bit, because I was pretty sure my code was good, but I didn’t have an eternity to wait. So I found someone else’s code, found the correct answer, then worked out my starting offset from there. Sure enough, when I start at 15,630,6390,084,400. It quickly finds the correct answer.

If I needed this code for something important, I would certainly try to clean it up. I even started working on an iteration that would sort out my bus list to start with the largest number, instead of iterating the list every (low value) it would iterate every (high value), which in my case I believe was something like 15 versus 900. This was trickier than a straight sort though because I had a second list of offsets that I needed to also re order. I got this code working for the sample data set, but it failed in my proper data set because, while the sample data set started with the lowest bus number, the actual data set did not, and I had not calculated for that.

PS, yes, I misspelled “busses” in my code

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