Question 109250 in Json Question posted in
Our archive of expertly curated questions and answers provides insights and solutions to common problems related to this popular data interchange format. From parsing and manipulating JSON data to integrating it with various programming languages and web services, our archive has got you covered. Start exploring today and take your JSON skills to the next level

Json – Reading Sudokus from text file and applying backtracking

I have just begun with python, so excuse me if these are noob questions or if the questions are already answered.
I am trying to read multiple sudoku puzzles and apply the algorithm I found online. The code utilizes a grid(list[list[int]]) setup. I have tried looking for a solution online, but all I found was that I should convert the .txt file to a JSON file and continue from there.

The .txt file looks like this:

AME: sudoku
TYPE: SUD
COMMENT: 5 sudokus

SUDOKU 1
034000600
002600080
068300007
003001005
059060072
000520046
205906000
000408050
000007004

SUDOKU 2
000504000
000089020
785000000
002346008
040290050
860000000
030007042
400060805
608005030

SUDOKU 3
040000300
036072000
078060400
083000600
000300005
025008070
300004800
000000024
764089530

SUDOKU 4
000074900
000000046
079000300
600728009
980503000
037940050
200000000
008030060
060490023

SUDOKU 5
026030470
000200510
700900020
509000000
000050000
000000307
080009001
034006000
095070640

EOF

Code from online:

def is_valid(grid, r, c, k):
    not_in_row = k not in grid[r]
    not_in_column = k not in [grid[i][c] for i in range(9)]
    not_in_box = k not in [grid[i][j] for i in range(r//3*3, r//3*3+3) for j in range(c//3*3, c//3*3+3)]
    return not_in_row and not_in_column and not_in_box


def solve(grid, r=0, c=0):
    if r == 9:
        return True
    elif c == 9:
        return solve(grid, r+1, 0)
    elif grid[r][c] != 0:
        return solve(grid, r, c+1)
    else:
        for k in range(1, 10):
            if is_valid(grid, r, c, k):
                grid[r][c] = k
                if solve(grid, r, c+1):
                    return True
                grid[r][c] = 0
        return False
        
grid = [
    [0, 0, 4, 0, 5, 0, 0, 0, 0],
    [9, 0, 0, 7, 3, 4, 6, 0, 0],
    [0, 0, 3, 0, 2, 1, 0, 4, 9],
    [0, 3, 5, 0, 9, 0, 4, 8, 0],
    [0, 9, 0, 0, 0, 0, 0, 3, 0],
    [0, 7, 6, 0, 1, 0, 9, 2, 0],
    [3, 1, 0, 9, 7, 0, 2, 0, 0],
    [0, 0, 9, 1, 8, 2, 0, 0, 3],
    [0, 0, 0, 0, 6, 0, 1, 0, 0]
]
solve(grid)
print(*grid, sep='n')

Instead of the static grid that needs to be inputted, I would instead use the .txt file. I just couldn’t find anything to help me solve the issue at hand. This might be because I am new to python or I need help understanding how to convert to JSON files.

How to convert txt file into json using python? I have looked at this, but I am unsure if this is even the right approach.

Any feedback is appreciated, or even a nod in the right direction is also helpful.

Tags:

2

Answers


  1. 0

    Here’s an example of how you could read the sudoku text file into a dictionary of list[list[int]], i.e. dict[str, list[list[int]]]:

    def read_sudokus(fn: str) -> dict[str, list[list[int]]]:
    sudokus = {}
    with open(fn) as f:
        [next(f) for _ in range(4)]  # skip the header
        while True:
            name = next(f).strip()
            if name == 'EOF':
                break
            sudokus[name] = [list(map(int, next(f).strip())) for _ in range(9)]
            next(f)  # skip blank line
    return sudokus


ss = read_sudokus('sudoku.txt')
print(ss)

    Output:

    {'SUDOKU 1': [[0, 3, 4, 0, 0, 0, 6, 0, 0], [0, 0, 2, 6, 0, 0, 0, 8, 0], [0, 6, 8, 3, 0, 0, 0, 0, 7], [0, 0, 3, 0, 0, 1, 0, 0, 5], [0, 5, 9, 0, 6, 0, 0, 7, 2], [0, 0, 0, 5, 2, 0, 0, 4, 6], [2, 0, 5, 9, 0, 6, 0, 0, 0], [0, 0, 0, 4, 0, 8, 0, 5, 0], [0, 0, 0, 0, 0, 7, 0, 0, 4]], 'SUDOKU 2':  etc.

    This assumes a standard sudoku size of 9×9 of course.

    Login or Signup to reply.
  2. 0

    The simple answer would be to read the lines of the txt file out and then search for the sudokus.
    It would look something like this:

    with open('sudoku.txt', 'r') as f:
    lines = f.readlines()

puzzles = []

for i, line in enumerate(lines):
    sudoku = []
    if line.startswith('SUDOKU'):
        # next 9 lines will be our puzzle
        for j in range(1, 10):
            sudoku.append([*lines[i+j].strip()]) # strip gets rid of the newline character, the * splits the string into a list of characters
        puzzles.append(sudoku)

    The puzzles list now contains a list of lists, but all of the characters are strings right now, I will leave the conversion into integers to you.

    Login or Signup to reply.
Please signup or login to give your own answer.

Back To Top
Search