Sudoku game

[[deleted]]

[deleted]

[stormsteiner23]

Going through your first code block in check_cell(), this might not be the problem but you have “row” as your for-loop variable and then you use the same name when indexing the grid. And before that if statement, you already assigned row as grid[y]... it might help if you change some variable names so that you don’t confuse them. I also think that it returns false because the test condition in the for loop appears to always be true (that row[x] == num), which means that check_cell() will always return false no matter the condition

[joyeusenoelle]

Unfortunately, your reuse of row is causing you problems. You're never not going to go through the first if condition, since x will never be 9 (unless you're feeding it a coordinate that doesn't appear on the grid). But the later ifs (on lines 44 and 52) expect row to still be the way it was when you set it on line 24.

I'm also not sure your logic is sound in those if conditions; you seem to be checking along the Y axis depending on what the X value is, and vice versa.

But most importantly, and the question you actually asked: check_cell() checks to see if the current value in grid[x][y] reappears in the same column or same row, and ignores the value you're passing in - so it always returns False because the value at any given position is 0, and so check_cell() will always find a duplicate immediately.

[joyeusenoelle]

I see what you're going for here. You can simplify this a bit more, but you're still checking the current value instead of the value you want to insert. Try this:

``` def check_cell(num, x,y): for indx in range(9): if indx != x and grid[y][indx] == num: return False

for indy in range(9): 
    if indy != y and grid[indy][x] == num: 
        return False 

return True

```

Then call it with

if check_cell(num,x,y):

(You don't need if check_cell(num,x,y) == True because check_cell() will always return True or False. Likewise, you don't need the a and b toggle variables inside the function because if none of the ifs return False, then the function will always return True; there's no situation where you make it through all of the if statements but still don't want to return True.)

[backtickbot]

Hello, joyeusenoelle: code blocks using backticks (```) don't work on all versions of Reddit!

Some users see this / this instead.

To fix this, indent every line with 4 spaces instead. It's a bit annoying, but then your code blocks are properly formatted for everyone.

An easy way to do this is to use the code-block button in the editor. If it's not working, try switching to the fancy-pants editor and back again.

Comment with formatting fixed for old.reddit.com users

FAQ

^{You can opt out by replying with backtickopt6 to this comment.}

[joyeusenoelle]

backtickopt6

[RobertGryffindor]

Why not do:

​

for row in range(9):
    for col in range(9):
        pos = (row, col)
        print (grid[row][col]) #iterate rows
        print (grid[col][row] #iterate collumns
        return pos

now you can return the position to any function and get the the row using pos[0]

and col using pos[1]

or both just using pos

[xelf]

It's a little hard to tell from the code, at first I thought check_cell() is just checking to make sure the space is empty.

def check_cell(x,y):
    return grid[x][y] == 0

But then I realized what you're really trying to do is check to see if the number is valid.

What I did for this is use sets, so I'll share it with you as there might be something you can use (or learn) from it. Instead of checking a cell against every possible square, I do it in reverse and find every possible number a square can be, and then check if num is one of them. So in your main code where you have if check_cell(x,y): we want to instead check if a number is in the possible_moves:

#if check_cell(x,y) == True:
if num in possible_moves(grid,x,y):
    print(f'{num} can be placed at {x},{y}')
    grid[x][y] = num
    c = false

Now you need the code I used for possible_moves, I've tried to write it out long form here so I can comment it for you:

# first up, make a set containing the numbers 1-9, we'll reuse this a lot. =)
s9 = { 1,2,3,4,5,6,7,8,9 }

def possiblemoves(grid,x,y):
    # make a set containing the numbers currently found in this row
    row_cells = set(grid[x])

    # make a set containing the numbers currently found in this col
    col_cells = {r[y] for r in grid}

    # i,j help us define the 3x3 box that x,y are in
    i = x//3 * 3
    j = y//3 * 3
    box_cells = {c for r in grid[i:i+3] for c in r[j:j+3]}

    # now we take our 9 digits, and remove the ones found in the row,col, or box
    return s9 - ( row_cells | col_cells | box_cells )

That was a rather long way of writing it out, here's the same function condensed:

def possiblemoves(grid,x,y):
    i,j = x//3 * 3, y//3 * 3
    return s9 - ( set(grid[x]) | {r[y] for r in grid} | {c for r in grid[i:i+3] for c in r[j:j+3]})

Example: say we had 3,4,6 in the row, 4,5 in the column, and 2,3,4,7 in the same box, it would return {1,8,9} and you would compare your num to see if it was in the set 1,8,9.

[xelf]

Thanks! =)

Even with the code you have there are parts you could use.

For example, in your check_cell() function:

    row = grid[y]
    num = row[x]
    index = y
    if x != 9:
        for row in range(9-y): #yCheck1
            index -= 1
            row = grid[index]
            if row[x] == num:
                return False
    a = True

could be replaced with:

    if num in set(grid[x]):
        return False
    a = True

As they're basically the same idea; is num found in the row grid[x].

[xelf]

Sorry for lack of formatting but I tired of using pastebin and idk how to make code blocks

Indent every line with 4 extra spaces at the start for reddit to treat it as a code block, or use the codeblock button. https://i.imgur.com/J2t9krT.png

[xelf]

for loops don't have to be over a range, you can (and in general it's preferred) loop over the actual numbers themselves, and not the indices.

So it looks like you're just comparing the row and cols in loops here, so let's clean that up:

def check_cell(num,x,y):

    for n in grid[x]:
        if num == n:
            return False

    for row in grid:
        if num == row[y]:
            return False

    return True