#🔒 Homework Help
sinful zenith
high marlin
Ugh let's try this again
I'm having trouble with this code identifying the Kings position (marked by a lowercase k) and I tried to make a sub-function to do it for me, but no matter where I put it, it doesn't work
.Q..kb.r
p..n.ppp
....q...
....p.B.
........
........
PPP..PPP
..KR....
Here's the txt file being used
I know this is a lot but the person helping me disappeared and I honestly have no idea what to do
pure crow
I'm having trouble with this code identifying the Kings position (marked by a lo...
wdym doesn't work?
which function identifies the king's position?
elfin needle
can't help fully rn but fyi don't test types like == None and == str. use is None and isinstnace(obj, str), respectively
pure crow
I'm having trouble with this code identifying the Kings position (marked by a lo...
OK I see the problem
def find_king_coords(x, y, board, height, width, King_Position):
for y in range(height):
for x in range(width):
if board [y][x] == "k":
return King_Position == (x, y)
When you do this: King_Position == (x, y), it returns True or False
If you're supposed to get the coordinates of the king, you should return x, y
floral pine
try something like x = board[y][x] and play with x
pure crow
not do a comparison
floral pine
how i work with dataframes anyhow
pure crow
also, not sure about that double loop and coordinate in board[y][x], whereas the return of the King position is (x, y)
high marlin
If you're supposed to **get** the coordinates of the king, you should return `x,...
Okay then, so after I fix that ( I just did) should I update the final function to do this?
def bk_in_check(board):
height = len(board)
width = len(board[0])
King_Position = None
for y in range(height):
for x in range(width):
King_Position = find_king_coords(x, y, board, height, width, King_Position)
if board[y][x] == None:
pass
elif board[y][x] == str:
if check_path(board, x , y , height, width, King_Position):
return True
else:
pass
Because if I call it before the loop I get an error
Oh I should probably
def find_king_coords(x, y, board, height, width, King_Position):
for y in range(height):
for x in range(width):
if board [y][x] == "k":
return (x, y)
What's the error?
mellow acorn
Yep. BTW, you don't need the brackets.
pure crow
I assume because you don't need the x, y in the function parameters
mellow acorn
Also, this: elif board[y][x] == str: If you want to know if there is a string in that position you want:
elif isinstance(board[y][x], str):
It won't be ==str because that will compare its value (some string like "k") with the type str. Never equal 🙂
high marlin
I assume because you don't need the x, y in the function parameters
line 184, in bk_in_check
find_king_coords(x, y, board, height, width)
^
UnboundLocalError: cannot access local variable 'x' where it is not associated with a value
pure crow
Yea that's what I thought
pure crow
Possibly but also not really
high marlin
Also
pure crow
You probably just need to remove x and y from both the find_king_coords function call and the function find_king_coords parameters
high marlin
Oh Mkay
Ill try that
Nope
It just gives me the wrong response
Still saying the Black King isn't in check
pure crow
It just gives me the wrong response
Wdym wrong response?
high marlin
```
.Q..kb.r
p..n.ppp
....q...
....p.B.
........
........
PPP..PPP
..KR....
```
^
The Black King is clearly in check
It's running the else incase it's not in check
pure crow
Black king is k, correct?
pure crow
Ok
high marlin
Lemme try something
Yea nvm
I was gonna try and have the function print the King Position somewhere
But it doesn't want to
AH
Got it
Yea so
It's not changing the value of King_position
Okay now it is
But it's still not...working
Okay think I found the issue
I tried also making the function report what position the Queen was checking
It never reported back
Which I think means that
The function isn't being called
So it is either a problem with
The value being returned by check_path
Or
elif board[y][x] == str:
if check_path(board, x , y , height, width, King_Position):
return True
else:
pass
This isn't being called
Welp
Looks like I was right
I changed it to
elif board[y][x]:
if check_path(board, x , y , height, width, King_Position):
return True
else:
pass
And immediately got
in check_path
if check_by_queen(x, y, King_Position):
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
TypeError: check_by_queen() missing 3 required positional arguments: 'board', 'height', and 'width'
Same error on check_path
mellow acorn
Sounds like check_by_queen wants 6 parameters and you only supplied 3.
mellow acorn
"missing 3 required positional arguments: 'board', 'height', and 'width'
"
high marlin
HAHA
Now lemme test this some more
Okay so
On the grading script it got one failure
I think I did something wrong with the Rooks code
Weird
The grading script doesn't get an error
But when I put the test file in myself
I get an index error
But I get
if board[y][x] == None:
~~~~~~~~^^^
IndexError: list index out of range
mellow acorn
This means that x or y is too big. (BTW, you want is None, not == None.)
Put a:
print("x =", x, "y =", y)
just before this line. At least you'll see what they are, which leads toward the problem.
Looks like the testing script expects all your indents to be by 4 spaces.
high marlin
I know about the styling stuff
I save that for last
Wanna get the code functioning before it looks ncie ya know
*nice
mellow acorn
Agreed.
high marlin
Okay so found it
It's going to an index of 8 for some reason
When the highest it goes is 7
Which is
Weird to say the least
The loop shouldn't make that possible
And considering the rest of the tests don't do it either..
mellow acorn
Might you be passing x+1 or similar when checking for adjacent cells? So at x == 7 you might do some test against x=8
mellow acorn
Maybe. Derpends on the tests.
high marlin
def bk_in_check(board):
height = len(board)
width = len(board[0])
King_Position = None
King_Position = find_king_coords(board, height, width, King_Position)
for y in range(height):
for x in range(width):
print("x =", x, "y =", y)
if board[y][x] is None:
pass
elif board[y][x]:
if check_path(board, x , y , height, width, King_Position):
return True
else:
pass
There should be nothing here causing that either
I'll check a subfunction rq
But's whats weird I notice
Is
It goes through EVERY row first
It gets through every row
And THEN manages to get the error
So it should be done checking by then
mellow acorn
It was definitely this line?
if board[y][x] is None
?
I guess you're seeing an 8, so it must be.
Add from pprint import pprint to the top of your script.
The after that print() above, add:
pprint(board)
Obviously x seems wrong. better check that the board is actually the shape you expect.
... and print height and width.
high marlin
It was definitely this line?
```py
if board[y][x] is None
```
?
Yes
Okay
Printed
x = 8 y = 7
[[None, None, 'R', None, None, None, 'k', None, '\n'],
['p', 'b', None, None, 'r', 'p', 'p', None, '\n'],
[None, 'p', None, 'p', None, 'n', None, 'p', '\n'],
[None, 'Q', None, 'p', None, 'q', None, None, '\n'],
[None, None, None, 'P', None, None, None, None, '\n'],
['P', None, None, 'N', None, None, 'P', None, '\n'],
[None, 'P', None, None, 'P', 'P', 'B', 'P', '\n'],
[None, None, None, None, 'R', None, 'K', None]]
I don't see anything wrong persay..
mellow acorn
And width?
high marlin
And it's only THIS board
mellow acorn
You don't modify x or width anywhere in this function?
Odd that it gets to y=7 before x=8. Should have failed for y=0 also. You'd think.
high marlin
Okay so uh
Called Height and Width
x = 8 y = 7
width is 9 height is 8
Huh???
Fuck you mean Nine????
high marlin
No no I mean
mellow acorn
Oh.
high marlin
It's clearly an 8 x 8
mellow acorn
You've got '\n' !!! You built this from reading a text file?
Show the code for that bit pls?
high marlin
I just copy and pasted the txt file from the testing script
mellow acorn
Right. But your program must read it in, yes?
mellow acorn
No? Where's board come from?
high marlin
x = 1 y = 0
width is 9 height is 8
[[None, 'Q', None, None, 'k', 'b', None, 'r', '\n'],
['p', None, None, 'n', None, 'p', 'p', 'p', '\n'],
[None, None, None, None, 'q', None, None, None, '\n'],
[None, None, None, None, 'p', None, 'B', None, '\n'],
[None, None, None, None, None, None, None, None, '\n'],
[None, None, None, None, None, None, None, None, '\n'],
['P', 'P', 'P', None, None, 'P', 'P', 'P', '\n'],
[None, None, 'K', 'R', None, None, None, None, '\n']]
This is the first test I was doing
high marlin
So what do I do then?
mellow acorn
Something must load values into the board list-of-lists. What does that?
high marlin
Lemme get it
'''py
Ffs
Im dumb
def read_board(filename):
board = []
f = open(filename, 'r')
for line in f:
row = []
for ch in line:
if ch == '.':
row.append(None)
else:
row.append(ch)
board.append(row)
f.close()
return board
There
Also
board = read_board("chess.txt")
Yeah. You want for ch in line.rstrip(). When you read lines of text from a text file, the trailing newline is included in the line. And you've thus included that newline in the board lists.
high marlin
So
mellow acorn
So line.rstrip() removes trailing whitespace from line, which is the newline in this case.
high marlin
Just add that to
for ch in line.rstrip()
for line in f:
?
Like that
I forgot the colon
But you get my point
mellow acorn
Swap the code lines. But yes. strip the line.
mellow acorn
Show new code. Show pprint(board).
high marlin
def read_board(filename):
board = []
f = open(filename, 'r')
for line in f:
for ch in line.rstrip():
row = []
for ch in line:
if ch == '.':
row.append(None)
else:
row.append(ch)
board.append(row)
f.close()
return board
And
[[None, None, 'R', None, None, None, 'k', None, '\n'],
[None, None, 'R', None, None, None, 'k', None, '\n'],
[None, None, 'R', None, None, None, 'k', None, '\n'],
[None, None, 'R', None, None, None, 'k', None, '\n'],
[None, None, 'R', None, None, None, 'k', None, '\n'],
[None, None, 'R', None, None, None, 'k', None, '\n'],
[None, None, 'R', None, None, None, 'k', None, '\n'],
[None, None, 'R', None, None, None, 'k', None, '\n']]
Still the newlines. You did save the file and reload the board etc?
mellow acorn
It should not be possible to have newlines if the rstrip() is there.
high marlin
Are you sure that's the right code you gave me?
mellow acorn
Is this a script, or something like a Jupyter file?
high marlin
A script
mellow acorn
Hey, why the 2 for loops?
for ch in line.rstrip():
row = []
for ch in line:
Move the upper for ch... to replace the lower for ch....
The lower for ch is iterating over the unstripped string, as before, thus the newlines.
mellow acorn
You had this before:
def read_board(filename):
board = []
f = open(filename, 'r')
for line in f:
row = []
for ch in line:
if ch == '.':
row.append(None)
else:
row.append(ch)
board.append(row)
f.close()
return board
I wanted you to change: for ch in line:
into: for ch in line.rstrip():
mellow acorn
Show updated code. Show pprint(board).
high marlin
And doing that
width is 8 height is 8
[[None, None, 'R', None, None, None, 'k', None],
['p', 'b', None, None, 'r', 'p', 'p', None],
[None, 'p', None, 'p', None, 'n', None, 'p'],
[None, 'Q', None, 'p', None, 'q', None, None],
[None, None, None, 'P', None, None, None, None],
['P', None, None, 'N', None, None, 'P', None],
[None, 'P', None, None, 'P', 'P', 'B', 'P'],
[None, None, None, None, 'R', None, 'K', None]]
There
But the issue is still there
The rook is not recognizing the King
high marlin
No
No
No
The width value comes the width variable
Not x
Its the len of x
Well not
Its
width = len(board[0])
Anyways I still have my issue
mellow acorn
Yeah, and that was 9 when you had your IndexError. And now it should be 8.
high marlin
The ROOK is still not recognizing the King as being in check
high marlin
Yeah, and that was 9 when you had your `IndexError`. And now it should be 8.
Yes, and it still isn't fixed
I still get
"Black king is not in check."
mellow acorn
Still getting the indexError?
high marlin
No it just won't recognize the King as being in check
When it clearly is
..R...k.
That is check
mellow acorn
Then you need to show the code which checks the rook check stuff/
high marlin
And it doesn't see it somehow
mellow acorn
That is indeed check.
high marlin
def check_by_rook(x, y, King_Position, board, height, width):
moving_x = x
moving_y = y
while moving_x > 0:
moving_x -= 1
if (moving_x, y) == King_Position:
return True
if board[y][moving_x]:
break
while moving_x < width - 1:
moving_x += 1
if (moving_x, y) == King_Position:
return True
if board[y][moving_x]:
break
while moving_y > 0:
moving_y -= 1
if (x, moving_y) == King_Position:
return True
if board[moving_y][x]:
break
while moving_y < height - 1:
moving_y += 1
if (x, moving_y) == King_Position:
return True
if board[moving_y][x]:
break
return False
There
That's the sub function to check the Rooks surroundings
mellow acorn
Are (x,y) the position of the rook?
mellow acorn
So this scans left, then right, then up, then down?
high marlin
Their movement is tracked the same
high marlin
So this scans left, then right, then up, then down?
Yes
Idk why it's not returning a True value
I can show the Queens function too
Because I know it's always working
It never failed its tests
mellow acorn
Ah. You need to reset moving_x = x after the first moving_x loop. And reset moving_y = y after the first moving_y loop.
Because these loops change moxing_x or moving_y.
high marlin
Nor did the bishop
high marlin
Ah. You need to reset `moving_x = x` after the first `moving_x` loop. And reset ...
In that case, how do I do that then?
mellow acorn
Because I know it's always working
Testing can show the presence of bugs, but not their absence.
high marlin
Wait but
This issue didn't exist when the Queen was in the same position
To the left of the King
It got a check
And the Queen
Is just my code
Copy and Pasted
mellow acorn
Seaparet function to test the queen stuff? Go look at it.
high marlin
From the Bishop and Rook
I checked I have the script open
All Queen tests passed
Including diagonal, horizontal, and verticals
mellow acorn
As an example, this code:
moving_x = x
moving_y = y
while moving_x > 0:
moving_x -= 1
if (moving_x, y) == King_Position:
return True
if board[y][moving_x]:
break
while moving_x < width - 1:
moving_x += 1
if (moving_x, y) == King_Position:
return True
if board[y][moving_x]:
break
This scans left. Then when it scans right, it starts the scan where it stopped the scan in the loop before. Not starting from x.
high marlin
Then why isn't the Queen failing???
I have her check up, down, left, and right first
mellow acorn
No idea. Again: show the code.
mellow acorn
It is very dependent on the board being tested.
high marlin
def check_by_queen(x, y, King_Position, board, height, width):
moving_x = x
moving_y = y
while moving_x > 0 and moving_y > 0:
moving_x -= 1
moving_y -= 1
if (moving_x, moving_y) == King_Position:
return True
if board[moving_y][moving_x]:
break
while moving_x < width - 1 and moving_y < height - 1:
moving_x += 1
moving_y += 1
if (moving_x, moving_y) == King_Position:
return True
if board[moving_y][moving_x]:
break
while moving_y > 0 and moving_x < width - 1:
moving_y -= 1
moving_x += 1
if (moving_x, moving_y) == King_Position:
return True
if board[moving_y][moving_x]:
break
while moving_y < height - 1 and moving_x > 0:
moving_y += 1
moving_x -= 1
if (moving_x, moving_y) == King_Position:
return True
if board[moving_y][moving_x]:
break
while moving_x > 0:
moving_x -= 1
if (moving_x, y) == King_Position:
return True
if board[y][moving_x]:
break
while moving_x < width - 1:
moving_x += 1
if (moving_x, y) == King_Position:
return True
if board[y][moving_x]:
break
while moving_y > 0:
moving_y -= 1
if (x, moving_y) == King_Position:
return True
if board[moving_y][x]:
break
while moving_y < height - 1:
moving_y += 1
if (x, moving_y) == King_Position:
return True
if board[moving_y][x]:
break
I put the original board at the top too
Passed that as well
high marlin
I put the original board at the top too
Top of the thread
You can see it's just the rooks code
mellow acorn
This has the same bugs. You need to reset moving_x and moving_y befor each loop so that they start from the correct position (the position of the queen. Or the rook.)
high marlin
And then the diagonal movement I stole from the Bishop
high marlin
This has the same bugs. You need to reset `moving_x` and `moving_y` befor each l...
It obviously doesn't have the same bug
It's not failing
It always puts the King in check
When its to the left or right
mellow acorn
If it finds the king in the first loop, the bug for the second loop does not affect the outcome. Come on, think about this.
Need to go AFK.
high marlin
Then how is the Queen able to pass the Diagonal test???
It shouldn't be able to
Because it's moving coords should be ruined
And yet a perfect test
Every time
And JUST in case I still don't convince ya
I will show every board for the Queen tests
rnbQk..r
ppp..pb.
.....n.p
....p.p.
....P...
..N..P..
PPP.N.PP
R.B.KB.R
r....rk.
.pp..p.p
..n..p..
pq..p...
....P.Q.
P.BP..P.
.....PKP
..R..R..
..r.....
.b..ppk.
.qn...pp
..pp....
.p..N...
.P.PP.P.
R.P..PBP
Q.....K.
.....bk.
...R.Qp.
.p..p..p
.P......
.q.p..P.
........
....PP.P
..r..BK.
r....r..
..p..k..
.p.p.Qp.
p......p
..P....P
......P.
PP...PK.
...R.R..
As you can see, the king is only horizontal to the Queen ONCE
Not to mention
........
R....k..
..P.....
.P..r.p.
.K......
........
....b..P
........
This is the first Rook test
Which PASSES
A rook
To the left of the king
Just like this test
It either has to be the Y value
Which should come SECOND in the code
As the X value gets changed first
Or
I don't know
If anyone else may be willing to interject, please do
It's 1 AM and I'm beginning to go hungry
mellow acorn
To the left of the king
A rook to the left is the first loop. That loop works.
Have you a test for the rook to the right of the king?
mellow acorn
I might have left and right swapped in my head here.
high marlin
Okay
Did the test that wasn't working
Swapped the Rook and King
Bingo
Works fine
Swap em back
Aaaand
Loud incorrect buzzer
mellow acorn
Right.
high marlin
So idk what this thing wants
mellow acorn
Was it King left of rook which worked?
high marlin
Yes
mellow acorn
Yeah. That is the first loop.
high marlin
```
........
R....k..
..P.....
.P..r.p.
.K......
........
....b..P
........
```
This
This passes fine
mellow acorn
So think about the second case, rook right of king.
With this code:
moving_x = x
moving_y = y
while moving_x > 0:
moving_x -= 1
if (moving_x, y) == King_Position:
return True
if board[y][moving_x]:
break
while moving_x < width - 1:
moving_x += 1
if (moving_x, y) == King_Position:
return True
if board[y][moving_x]:
break
With king to the left, the first loop finds it and we return True.
With king to the right, you need the second loop.
mellow acorn
When you commence the second loop, what is the value in moving_x?
high marlin
This the same scenaior
*scenario
A rook the left of the king
It is not
The X value
mellow acorn
You just told me that king-left-of-rook passes and rook-left-of-king fails.
high marlin
If you are right
This
Should not
Be able
To pass
Look at it
It is another Rook to the left
Passing the test
In broad daylight
mellow acorn
Aye. But notice: in the test, the rook is at the left-most position. The first loop does nothing.
Which means it does not "damage" the value of moving_x.
high marlin
Yes and the loop prevents itself from gaining values that cannot exist
mellow acorn
Move the rook to position 1, not 0, and retry.
mellow acorn
Sure it does.
We've got the rook-left-of-king failing, which is what we need to fix, yes?
high marlin
Isn't that what
while moving_x > 0: and while moving_x < width - 1: does?
These should keep it going till it reaches its max value
Or min
mellow acorn
The bug I'm trying to describe is that at the end of the first loop, if the scan-left did not find the king, we end up with moving_x==0.
Does that make ense? Ignoring everything else: just the value after the first loop.
mellow acorn
Back up. Do you think this is true? That moving_x==0 after the first loop? Or not?
mellow acorn
If the rook is left of the king, the scan-left first loop will not find the king, yes? So it runs all the way to the end, and moving_x==0.
high marlin
Yea
mellow acorn
Ok.
So: the scan-right. What positions on the board do you intend it to scan? Those from the right of the rook up to the king (or the end of the row)? or other positions?
high marlin
To the right until it either
A. Finds a king
B. Finds a piece blocking it
C. Reaches the end of the board
mellow acorn
Ok. So it should start the scan at x+1?
mellow acorn
No.
high marlin
moving_x += 1
mellow acorn
It starts the scan at moving_x. Which you have just made 0.
high marlin
Okay but
mellow acorn
Not okay!
mellow acorn
Yes.
mellow acorn
That s why you need to reset moving_x = x before the second loop.
high marlin
Not do that?
Like is there any way to reset that value back to x before the next loop?
mellow acorn
So just put:
moving_x = x
just before the second loop.
high marlin
Aight
mellow acorn
You have the same problem with every single second loop, for moving_x or moving_y accordingly.
mellow acorn
Better?
high marlin
Yes
mellow acorn
Have they taught you about the range() function?
high marlin
Yea
mellow acorn
Ok.
high marlin
But briefly
mellow acorn
I would write those loops using for and range.
Example:
for moving_x in range(x-1, -1, -1):
.......
and:
for moving_x in range(x+1, width, 1):
.......
The range(start,stop,step) function counts from start up to, but excluding, stop, in increments of step.
So to scan left we start from x-1, go to -1 (excluding -1 itself) in steps of -1.
To scan right we go from x+1 to width (excluding width itself) in steps of 1.
The for-loop sets moving_x and you don't need to assign to it directly at all, or increment/decrement it.
high marlin
I see
I'll keep it in mind for the next time I gotta do something like this then
For now I'm gonna clean this up and finally eat something
mellow acorn
Good.
