Hi, I found this sudoku solver online and it works good but I was wondering how I could get the answer that's in matrix form, to also print out in a single comma-delimited line, instead of 9 rows of 9?

``````from copy import deepcopy

class Matrix:
def __init__(self, input):
self.rows = [[] for i in range(9)]
self.cols  = [[] for i in range(9)]
self.submatrices = [[] for i in range(9)]
self.cells = [Cell(i,self) for i in range(81)]
self.subdiagonals = [self.rows[i][j+i%3] for i in range(9) for j in [0,3,6]]
input = [s not in '-*' and int(s) or 0 for s in input if s in '0123456789-*']
for cell,val in zip(self.cells, input):
if val: cell.setSolution(val)

def solve(self): #Brute-force solver
self.solveByReduction()
lensols=[(len(c.solutions),c.index) for c in self.cells if not c.solved]
if not lensols: return True
unsolved = min(lensols)[1]
solutions = list(self.cells[unsolved].solutions)
for s in solutions:
tmpmatrix = deepcopy(self)
try:
tmpmatrix.cells[unsolved].setSolution(s)
if tmpmatrix.solve():
self.update(tmpmatrix)
return True

def solveByReduction(self):
while True:
self.changed = False
for c in self.cells: c.solve()
for c in self.subdiagonals: c.skim()
if not self.changed: break

def update(self, m):
self.rows, self.cols, self.submatrices, self.cells, self.subdiagonals=\
m.rows, m.cols, m.submatrices, m.cells, m.subdiagonals

def __str__(self):
return "\n".join(str([c for c in row ])[1:-1] for row in self.rows)

class Cell:
def __init__(self, index, matrix):
self.solved = False
self.matrix = matrix
self.index = index
self.row = matrix.rows[index/9]
self.col = matrix.cols[index%9]
self.submatrix = matrix.submatrices[((index/9)/3)*3+(index%9)/3]
self.row.append(self)
self.col.append(self)
self.submatrix.append(self)
self.solutions = set(range(1,10))

def solve(self):
if self.solved: return
if len(self.solutions) == 1:
self.setSolution(self.solutions.pop())
else:
sol = set()
for cells in [self.row, self.col, self.submatrix]:
otherSolutions = self.cells2sols(cells, self)
sol |= (self.solutions - otherSolutions)
if len(sol) > 1: raise DeadEnd()
if sol: self.setSolution(sol.pop())

def skim(self):
submatrix = set(self.submatrix)
for r in  (set(self.row), set(self.col)):
subset1 = submatrix - r
subset2 = r - submatrix
solsNotIn1 = set(range(1,10)) - self.cells2sols(subset2)
solsNotIn2 = set(range(1,10)) - self.cells2sols(subset1)
for c in subset1: c.delSolutions(solsNotIn1)
for c in subset2: c.delSolutions(solsNotIn2)

def setSolution(self, val):
self.solved = True
self.solutions = set((val,))
self.matrix.changed = True
for other in self.row+self.col+self.submatrix:
if other is self: continue
if other.solutions == self.solutions: raise DeadEnd()
other.delSolutions(self.solutions)

def delSolutions(self, val):
if not self.solved and val & self.solutions:
self.solutions -= val
self.matrix.changed = True

def __repr__(self):
return str(self.solved and list(self.solutions)[0] or list(self.solutions))

@staticmethod
def cells2sols(cells, exclude=None):
return set(s for c in cells for s in c.solutions if c is not exclude)

if __name__ == "__main__":
input = '''5,6,7,2,3,0,0,0,1,2,0,0,0,9,1,5,6,7,8,0,1,0,0,0,2,0,4,0,5,0,1,2,0,7,8,9,0,2,3,0,0,0,0,5,0,0,8,9,0,5,6,0,2,3,0,7,0,3,4,5,0,1,2,3,0,5,9,1,2,0,7,8,9,0,2,6,7,8,3,4,5'''
matrix = Matrix(input)
matrix.solve()
print matrix``````
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9 Years
Discussion Span
Last Post by defience

I think, replace `"\n"` by `", "` in the method `__str__` of the `Matrix` class.

Yes, that works! Thanks!