DEV Community: lwolczynski

Movie comparison tool you may like (and my fresh portfolio as a bonus!)

lwolczynski — Sun, 14 Feb 2021 19:33:13 +0000

Quickly about the bonus

You can find my portfolio at lwolczynski.com. I've been tweaking it for a long time, so if you decide to visit, please let me know how you like it.

It’s hosted on Google Firebase which I’ve found is a pain to use if you don’t have any experience with. If you don’t know why, Firebase doesn’t give you full control of the back end. Instead, it forces you to use Cloud Functions that lets you automatically run backend code in response to events triggered by Firebase features^[1]. Long story short, this was a proprietary solution I needed to learn to make the contact form work.

If your next question is: ‘Why did you use Firebase, not a different platform like Heroku?’, the answer is: Heroku would charge $7 for using the features I need (mostly Nodemailer and keeping my website active when there’s no traffic). Cloud Functions requires a Firebase subscription plan, but it’s pay-as-you-go and I don’t expect to get enough traffic to be charged (not yet, at least).

If you’re interested in learning more, I plan to write a short article on how use their database and functions, as it didn’t come easy to me. Stay tuned!

Movie comparison tool

The main event (and something you may use more) is a web app I named Pick-A-Mov. Pick-A-Mov is a movie comparison tool I created with ReactJS, Express, Semantic UI and an external API to fetch information about movies. It allows you to compare up to 4 movies, including their ratings, on IMDB, Rotten Tomatoes, and Metacritic. The idea came from the most popular JavaScript course that you may have come across on Udemy (it’s a good one, thumbs up). The project in the course was built with VanillaJS, but I decided to take it a step further and use React, which seemed to be an obvious choice for this kind of website — and made it look better, too.

If you come across this, it's built step-by-step from the tutorial

My implementation. Looks better, huh?

If you’ve ever wanted a tool that will allow you to quickly compare top movie contenders and help you decide what to watch, here you go. Use it as much as I do and share your thoughts: good comments, bad comments, ideas, kudos, complaints, queries, I’m happy to hear them all. Let me know!

Til’ next time!

Find my code on GitHub:

lwolczynski / Movie-Comparison

Web app that lets user get details about up to 4 movies and compare their ratings on the most popular websites

[1] Cloud Functions docs

I created a music quiz and it's awesome

lwolczynski — Tue, 29 Dec 2020 22:19:51 +0000

Tl;dr: If you are a Spotify user, go to spotiquiz.com and check it out (I have no tl;dr for the Spotify-agnostics, sorry...)

The idea

Let's start here with an idea that I had for a while. Create something cool and learn new tools to do it. This app will be a part of my portfolio and I want it to be useful, easy to use and well... cool. Do people like to play quizzes they find on the Internet? I think so. Sporcle.com creators probably know something about it. Music quizzes? Probably. (Hey, Sporcle, you're missing out here, by the way.) How about music quizzes with the songs the user actually listens to...?

Picking the tools was rather easy. Spotify WebAPI gives user access to playlists, album covers and songs previews. What else would I need? A Spotify account? Luckily enough, I'm a user. By the way, if you are looking for an API to play with or learn how to use them, I would highly recommend this one. It supports four different ways of authorization and gives a pretty vast set of requests to choose from.

What's next? I felt like I didn't need backend for this app and I could make it a client-side app. I figured React would be something I could utilize here and I wasn't wrong. It's been a journey to understand the concept and learn the basics, but from there it started to be fun with a splash of frustration from time to time. I've been using a course on Udemy to understand and learn React. I'm leaving a link here if you're interested.

Combining these three together (idea of a music quiz, Spotify WebAPI and React) I created an app I've called SpotiQuiz. The link is on the top, the code is on the bottom. I hope you give it a try and have a lot of fun.

Is it cool?

You let me know! I think it is, but I guess I'm biased, so I'll gladly take good reviews, bad reviews, hints what to change and where to upgrade.

Find my code on GitHub:

lwolczynski / Spotify-Quiz-v2

Music quiz using Spotify music library

My first fully functional web app is here!

lwolczynski — Wed, 26 Aug 2020 03:39:49 +0000

Play golf, disc golf or foot golf and create your personal scorecard to compete with friends! Easy to use, easy to share. Visit myscore.golf

What it's about

So what do you do when unexpectedly, everything but parks in your town is closed? If you answered: go to a park and play disc golf, we are in the same boat. You go there and you take a piece of paper and a pen to follow yours and your friends' scores. After a couple times a little imaginary bulb lights up over your head. The idea is here. Let's track it them on your phone. Golf score trackers online? Many. But then you find that they add features you will never use and they want you to pay. You want a simple tracker though. What do you do? Build one!

As the idea was there, I got to work. Django, jS, SQL are things I've learned before, so I had no other choice than use them. Nobody minds a little practice. A friend said, don't use Bootstrap, you'll learn more about CSS. Say no more. After 5 weeks, the website is here. Built from scratch. Mobile-friendly and intuitive. The goals I had in mind were: make it look good and don't over-complicate it. It went well. Well enough to share it. You tell me what you think!

My plan now is to find people who will use it. And again, it's not for people crazy about golf that I don't know much about. But hey, mini-golfers! Disc golfers! Foot golfers! I have something for you! And even if not, it was a learning experience and I will use it with my friends, so nothing goes to waste!

What I found

It's been a journey and learning process. Many libraries, extensions, properties and tools I used for the first time. Things happened to me for the first time. Let's see...

Bought first domain and first domain was 'stolen' from me: The first part of this statement is actually a half-lie. I used to have a domain, but the first year was free, so technically I didn't buy it. Let's talk about the second part that is more interesting. My app was supposed to be called MyScores instead of MyScore, but when I was shopping around and checking prices for that domain, I went to GoDaddy and... of course never bought from them, but the next day when trying to buy from name.com I found it had been taken! Quick look at whois.net showed me this: Well, GoDaddy, I never asked you to register what I searched for... I'll be more cautious next time.
Practiced creating elements with different display and position properties: Words like flexbox, sticky, absolute became my friends. A website describing the rules that apply to them turned out to be my most visited website in the last couple weeks.
Used Axios and Promises for the first time: And what an experience it was. This is a crucial functionality of my web app. I couldn't make it work without asynchronous functions. What I found out about them? They take time to understand and it doesn't come easy.
Found that Prettier doesn't get along with Django tags: Decided to use Beautify instead. As Prettier seems to be way more popular, I'm not done with it. I'll give it a second chance.
Got my first experience with Google Analytics: Oh, Google. When I watch your trackers I'm kinda scared. If this is what you know about my users, I'm afraid to think of what you know about me.

Next steps

I like having goals even if I'm making them for myself. I write them down on sticky notes and put them on my laptop. This way they remind me every day what I should do next. So what are they currently saying?

For the website:

SEO: I'm totally new to this. It would be nice to see my page showing up in Google, not only when I put site:myscore.golf in the search bar. Organic traffic is the traffic we always hope for. That being said, let me know if you have tips and tricks for me.
Figure out why my emails go to spam: Being new to things is not easy. I've never created a web app that would send emails to the users. I went with SendGrid. It wasn't difficult to make it work, but it's an effort to make it work well. When an email is sent to a GMail account, it always lands in the spam folder. Why? Still a mystery to me, but I will find out!
New features: Practice, practice, practice. I have ideas of features I would like to add. The app works, but it's time to make it even cooler. Every new line of code is a way to learn.

For myself:

Continue learning jS: I was focused on building this web app, so the course on Udemy I've started had to wait. Udemy, we haven't seen each other for a while, but...
Build portfolio: Yes, the time has come. I was thinking about for a while, but felt like I didn't have enough to share. Now, when I have a fully functional web app that I'm proud of, it's time to do it.
Learn more than just jS: The plan looks pretty straight-forward now. Two things on the horizon: Node and React. And my boat is headed that way.

See you in a flip.

Find my code on GitHub:

lwolczynski / Scores-Tracker

Web app that creates a personal scorecard to compete with friends at golf, disc golf or foot golf

I created my first game in JS

lwolczynski — Sun, 05 Jul 2020 19:18:28 +0000

Consistency is the key they say. Look at me posting every three months like your favorite quarterly magazine.

How have you been?

Before we get to the main topic, I've been recently working on the JavaScript course recommended to me by one of my friends. I found it very interesting if you want to learn JavaScript from scratch, but it also taught me a different way of organizing the code and keeping it clean. I can recommend it to you the same I did with the CS50 Web Development path I finished. Working on the Udemy course makes me think of what I should learn next. Master JS, learn React, get familiar with TypeScript? Feel free to let me know what your experience and ideas are!

The Game

Without a further ado - check it our here!

It's a simple game I decided to build to test my coding skills. I have to say I enjoyed coding it, as I'm happy with the outcome. It is simple, but I feel like simple is an answer to most things. Simpler is better, easier to understand, faster to troubleshoot, more intuitive to work with. And this is one of those! One of the games for which instructions are not necessary - like Flappy Bird or Minesweeper. Check it out, have fun, let me know how you like it and how it could be improved!

What's next

At the same time as I'm working on the JS online course, I've been working on my first project that I hope to get real users involved in. I have my domain, I have an idea how to host it and I'm working on polishing the front-end and finishing the back-end. I'll keep the rest of it as a secret for now and come back to it in my next post which may actually break the quarterly magazine rule.

Find my code on GitHub:

lwolczynski / Track-Game

Simple game wrote in JavaScript. Stay on track as long as you can!

How I deployed my first Python website on Heroku with CS50

lwolczynski — Wed, 01 Apr 2020 01:39:26 +0000

Finding online learning resources is easy. But finding the ones that you will like is not that straight-forward.

Search for the right tools

Coursera, edX, FreeCodeCamp, Codecademy and many many more. There are a lot of websites that will help you learn coding. You can try to use them all — been there, done that — but you may struggle to find something that you enjoy watching and/or reading. I started many online programming courses that I was forcing myself to finish, but did not really know if I wanted to. And then, I found the one that I got me hooked for good.

If you have not heard of CS50, I encourage you to give it a try. Interesting lectures, challenging projects and great community is the short way I would describe it. They do not only teach programming, they also give you tools. I never knew how to take a step forward, I have always kept all my work on my laptop and never knew how to deploy it to see more than just localhost in the address bar. CS50 is how I found about Heroku and CS50 is where I found a project to post.

The first project

The course I got into is Web Programming with Python and JavaScript and is available on edX. The first project (of three) focuses on Python, Flask and SQL. No need for JavaScript so far, but it is about to come along with different frameworks. What you are asked to build is a book review website (more details). Thus this is what I have created.

If you want to give it a try, if you want to try to break it, if you want to check it out and tell me what you think, you can find it here. It may be not sophisticated and complex, but this is just the beginning. I do not know yet if it is about the journey or destination, but I hope to find out.

Find my code on GitHub:

lwolczynski / CS50-Project1

Book review website build with Flask loosely based on CS50 Project 1 requirements

How to solve Sudoku faster than with backtracking?

lwolczynski — Fri, 03 Jan 2020 04:12:04 +0000

Tl;dr: Solve some cells before proceeding with backtracking!

I always liked solving mathematical puzzles and always struggled with finding entertaining and challenging problems to practice coding. That said, when the idea of writing a script that would solve Sudoku in a more sophisticated way than just using the backtracking method came to my head, I started thinking about the solution right away.

The Idea

Backtracking, which is pretty much placing numbers in empty cells and checking if a Sudoku board is still valid seems to be an inefficient way of solving the problem. The solution will be found eventually (if there is a solution), but why not try to apply additional logic to it? The same logic that is applied by people using a pencil on the last page of the newspaper with a printed puzzle.

I implemented some rules to make backtracking easier. Every cell that is solved beforehand reduces the set of solutions dramatically and makes script run much shorter. Two rules I decided to apply are the ones that anybody who has ever solved Sudoku uses and can describe.

Find a cell that only one number can be placed into:

There is not much effort required to find cells where only one number can be put. You pick a cell and think of possibilities by eliminating the numbers that are already written in the given box, column and row. You found there is only one option? You found the solution.
Find a box/column/row where a number can be put only in one cell:

Time to apply reverse logic here. Instead of looking for a cell that has only one possibility which makes it valid, you look for a box, column or row and check if one of the numbers that is missing from it can be placed only in one spot.

After determining these rules, I decided to find a way I would like my script to run. Here is the simplified algorithm flowchart that describes how the first part of my script works:

Simple as it is. Straightforward rules we have all applied to solve Sudoku. The most interesting is still to come though: backtracking.

When I first thought about implementing backtracking in my code, I did not know that recursion is not the best way of writing algorithms in Python. I fully implemented a way to solve the problem recursively, as backtracking seemed to be a perfect example of using it, and had to rewrite this part of the code, pretty much from scratch. Still, lesson for the life. Here is how I implemented backtracking after all:

The Code

With that explained, here is my code:



import time #used to check script's run time

#class representing a single cell of sudoku board
class Cell:
    def __init__(self, row_number, column_number, value):
        self.row = row_number #0 thru 8
        self.column = column_number #0 thru 8
        self.box = self.set_box_number() #0 thru 8
        self.value = value #0 if empty cell
        self.possibilities = self.set_initial_possibilities() #empty list or 1 thru 9

    #set box number based on row and column number
    def set_box_number(self):
        box_number = int(self.column/3)
        box_number += int(self.row/3)*3
        return box_number

    #set possibilities to empty list if cell not empty or 1 thru 9
    def set_initial_possibilities(self):
        if self.value != 0:
            return []
        else:
            return [*range(1, 10)] 


#class solving sudoku in 'human' way
class Solver:
    def __init__(self, board):
        self.cells = []
        for row_no, row in enumerate(board):
            for col_no, val in enumerate(row):
                self.cells.append(Cell(row_no, col_no, val))

    #get all cells from box
    def get_cells_from_box(self, box_number):
        return [cell for cell in self.cells if box_number == cell.box]

    #get all cells from column
    def get_cells_from_column(self, column_number):
        return [cell for cell in self.cells if column_number == cell.column]

    #get all cells from row
    def get_cells_from_row(self, row_number):
        return [cell for cell in self.cells if row_number == cell.row] 

    #get all cells within same box, column and row as given cell
    def get_conflicting_cells(self, given_cell):
        return {cell for cell in self.cells if given_cell.box == cell.box or given_cell.column == cell.column or given_cell.row == cell.row} 

    #remove not valid possibilities from all cells
    def set_all_cells_possibilities(self):
        for cell in self.cells:
            self.remove_cell_value_from_others_possibilities(cell)

    #look for a cell with single possibility and solve it
    def find_and_solve_cell_with_one_possibility(self):
        for cell in self.cells:
            if len(cell.possibilities) == 1:
                self.solve_cell(cell, cell.possibilities[0])
                return True
        return False

    #look for unique possibilities in all boxes, column and rows
    def find_and_solve_unique_possibilities(self):
        for number in range (0, 8):
            if self.if_unique_possibility_within_cells(self.get_cells_from_box(number)):
                return True
            if self.if_unique_possibility_within_cells(self.get_cells_from_column(number)):
                return True
            if self.if_unique_possibility_within_cells(self.get_cells_from_row(number)):
                return True
        return False

    #look for unique possibility in group of cells
    def if_unique_possibility_within_cells(self, same_group_cells):
        counts = [0] * 10
        for cell in same_group_cells:
            for possibility in cell.possibilities:
                counts[possibility] += 1
        if 1 in counts:
            unique_value = counts.index(1)
            for cell in same_group_cells:
                if unique_value in cell.possibilities:
                    self.solve_cell(cell, unique_value)
                    return True
            return False

    #solve cell and remove its value from other cells possibilities
    def solve_cell(self, given_cell, value):
        given_cell.value = value
        given_cell.possibilities = []
        self.remove_cell_value_from_others_possibilities(given_cell)

    #remove cell value from possibilites of cells within same box, column and row
    def remove_cell_value_from_others_possibilities(self, given_cell):
        for conflicting_cell in self.get_conflicting_cells(given_cell):
            try:
                conflicting_cell.possibilities.remove(given_cell.value)
            except:
                continue

    #main algorithm of the class
    def run(self):
        while(True):
            if not self.find_and_solve_cell_with_one_possibility():
                if not self.find_and_solve_unique_possibilities():
                    break


#class solving sudoku with backtracking algorithm
class Backtrack():
    def __init__(self, cells):
        self.cells = cells
        self.unsolved_cells = [cell for cell in self.cells if cell.value == 0]

    #get all cells within same box, column and row as given cell
    def get_conflicting_cells_values(self, given_cell):
        return {cell.value for cell in self.cells if given_cell.box == cell.box or given_cell.column == cell.column or given_cell.row == cell.row} 

    #check validity of sudoku if cell is set to given value
    def if_solution_valid(self, given_cell, cell_value_to_check):
        return not cell_value_to_check in self.get_conflicting_cells_values(given_cell)

    #check current cell value and pick next of its possibilities
    def get_next_possibility(self, given_cell):
        if given_cell.value == 0:
            return given_cell.possibilities[0]
        else:
            return given_cell.possibilities[given_cell.possibilities.index(given_cell.value)+1]

    #main algorithm of the class
    def run(self):
        current_cell_number = 0
        while (current_cell_number >= 0 and current_cell_number < len(self.unsolved_cells)):
            current_cell = self.unsolved_cells[current_cell_number]
            try:
                #get next possibility for cell
                next_possibility = self.get_next_possibility(current_cell)
            except IndexError:
                #no more possibilities for cell -> take step back and work on previous cell
                current_cell.value = 0
                current_cell_number -= 1
            else:
                #possibility valid -> change cell value and proceed to next cell
                if self.if_solution_valid(current_cell, next_possibility):
                    current_cell.value = next_possibility
                    current_cell_number += 1
                #possibility not valid -> change cell value and repeat process
                else:
                    current_cell.value = next_possibility


#class responsible for printing sudoku board in readable form
class Printer():
    def __init__(self, cells):
        self.cells = cells

    #print sudoku board
    def print(self):
        last_cell_row_no = 0
        for cell in self.cells:
            if last_cell_row_no != cell.row:
                print()
            print(cell.value, end = " ")
            last_cell_row_no = cell.row
        print("\n- - - - - - - - -")


#class responsible for checking if sudoku solution is valid
class Validator():
    def __init__(self, cells):
        self.cells = cells

    #check if sudoku solution is valid
    def if_valid(self):
        for cell in self.cells:
            if cell.value == 0:
                return False
        return True

    #print sudoku validity
    def print(self):
        if self.if_valid():
            print("Sudoku solved!")
        else:
            print("Sudoku is not valid!")


### main part below ###
def main():

    #sudoku to solve
    sudoku_to_solve = [
    [0, 0, 0, 0, 0, 0, 2, 0, 0],
    [0, 8, 0, 0, 0, 7, 0, 9, 0],
    [6, 0, 2, 0, 0, 0, 5, 0, 0],
    [0, 7, 0, 0, 6, 0, 0, 0, 0],
    [0, 0, 0, 9, 0, 1, 0, 0, 0],
    [0, 0, 0, 0, 2, 0, 0, 4, 0],
    [0, 0, 5, 0, 0, 0, 6, 0, 3],
    [0, 9, 0, 4, 0, 0, 0, 7, 0],
    [0, 0, 6, 0, 0, 0, 0, 0, 0]
    ]

    start_time = time.time() #start timer to measure run time

    solver = Solver(sudoku_to_solve)

    printer=Printer(solver.cells)
    printer.print()

    solver.set_all_cells_possibilities() #checks possibilities for all cells
    solver.run() #comment this line to leave everything to backtracking

    backtrack=Backtrack(solver.cells)
    backtrack.run()

    printer=Printer(backtrack.cells)
    printer.print()

    validator=Validator(backtrack.cells)
    validator.print()

    print("Run time: %s seconds" % (time.time() - start_time))

if __name__ == "__main__":
    main()

Summary

The code follows the idea shown in the algorithm flowcharts: a way to solve Sudoku faster than just with backtracking. This can be proven: run the script twice, first with solver.run() left out as it is, and second without that line (or with # before it) to skip the part that simplifies Sudoku before backtracking kicks in. Depending on the complexity, run time may decrease significantly. In the example written in the script, my run times are approx. 6.9 vs 64 seconds.

This could be even faster if more complex Sudoku solving rules were used. I will leave it as it is for now, as I am happy with the result. These simple rules helped to find a solution much faster already.

Find my code on GitHub:

DEV Community: lwolczynski

Movie comparison tool you may like (and my fresh portfolio as a bonus!)

Quickly about the bonus

Movie comparison tool

lwolczynski / Movie-Comparison

Web app that lets user get details about up to 4 movies and compare their ratings on the most popular websites

I created a music quiz and it's awesome

The idea

Is it cool?

lwolczynski / Spotify-Quiz-v2

Music quiz using Spotify music library

My first fully functional web app is here!

What it's about

What I found

Next steps

For the website:

For myself:

lwolczynski / Scores-Tracker

Web app that creates a personal scorecard to compete with friends at golf, disc golf or foot golf

I created my first game in JS

How have you been?

The Game

What's next

lwolczynski / Track-Game

Simple game wrote in JavaScript. Stay on track as long as you can!

How I deployed my first Python website on Heroku with CS50

Search for the right tools

The first project

lwolczynski / CS50-Project1

Book review website build with Flask loosely based on CS50 Project 1 requirements

How to solve Sudoku faster than with backtracking?

The Idea

The Code

Summary

lwolczynski / Sudoku-Solver

Python script to solve Sudoku by looking for unique possibilities and applying backtracking method