How to Program Connect 4 in Python! (part 2) - Check for Winning Move

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In this video we finish the command line version of our connect four game. We implement a way to check for a four in a row and talk a little bit about good design practices.

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[walterwhite]

Congrats, your channel has some pretty nice content, subscribed.

[Dhanush]

Thanks for this video now it's helping in my python class thank you.

[devanshukumar]

If we take WIN_NO as the number of pieces we need to arrive to win (traditionally 4), the code can be manipulated as -
def winning_move(board, piece):
for c in range(COLUMN_COUNT+1-WIN_NO):
for r in range(ROW_COUNT):
ctr = False
for i in range(WIN_NO):
if board[r][c+i] == piece:
ctr = True
else :
ctr = False
break
if ctr == True:
break
if ctr == True:
break
if ctr == True:
return True
This one is for horizontal rows, vertical and diagonal can be done similarly.
Using this you can make connect 4, connect 5, connect 8, connect 3 etc as long as the no. of rows and columns are appropriate; for eg, you can't have connect 10 in 7X8 grid.

[RJLVideography]

super easy to follow along and the explanations help without bombarding me with too more information

just having a problem with some edge cases...whenever 2 of the same coloured piece are placed at the top of the board (after being stacked) it is resulting in a win for that player...i've gone through this video and my code multiple times...and it doesnt make any sense, when i # out the vertical section of the winning move it doesn't happen, so i'm guess its something in that?

anybody got any ideas?

[samliew]

Is there others way to code winning moves?

[nilanpindoria]

How would you go about highlighting the winning move?

[miguelacevedo]

What if the winning ship was placed in between chips. In this case it is not an endpoint and the algo with not work?

[Kanglese]

You only need to check the row and column of the spot just played.

[miscany]

Hey little confused at 7:33. I don't see why remove 3 from a column of 7, and remove 3 from a row of 6?
It works, but I figured you would remove 1 more from the longer side?

[tobywebb]

Awesome video, although I find the np.flip does not do anything, any advice? I am using verson 3.7

[kohntv]

hi how do i implement wins if my board is 7 rows by 6 columns? im confused thank you..

[kyleeames]

Dude, just iterate over a sequence of vectors and scan along those vectors starting where the last piece was placed. It makes a very compact and readable function. I do something similar in my Othello game to test whether a move is valid, make a move, and simulate a move in my player bot.

[rollergamer]

How many possible wins are there in connect 4 ?

[TheLolobag]

After I start the game P1 plays and then after only P2 plays, help how do I correct that???

[thisistotalfck]

def winning_move(board, piece):
p = re.compile("(" + str(piece) + ".( )?){4}")
# vertical
for c in range(COLUMN_COUNT):
if p.search(str(board[:, c])) is not None:
return True

# horizontal
for r in range(ROW_COUNT):
if p.search(str(board[r, :])) is not None:
return True

# diagonal
for offset in range(-ROW_COUNT+4, COLUMN_COUNT-3):
if (p.search(str(np.diagonal(board, offset))) is not None or
p.search(str(np.diagonal(np.flip(board, 1), offset))) is not None):
return True