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My original efforts were in trying to generate random sudoku puzzles using lists. I want to make sure that while the sequences don't duplicate across (a "row"), they also don't duplicate vertically (like a column). Considering the use of lists as the sequence, the strategy was to use indexes to compare and "re-roll/-shuffle" any row, should it be found any indexes shared value.

This is the initial set up:

import random

row1 = ["1", "2", "3", "4", "5", "6", "7", "8", "9"]
row2 = ["1", "2", "3", "4", "5", "6", "7", "8", "9"]
row3 = ["1", "2", "3", "4", "5", "6", "7", "8", "9"]
row4 = ["1", "2", "3", "4", "5", "6", "7", "8", "9"]
row5 = ["1", "2", "3", "4", "5", "6", "7", "8", "9"]
row6 = ["1", "2", "3", "4", "5", "6", "7", "8", "9"]
row7 = ["1", "2", "3", "4", "5", "6", "7", "8", "9"]
row8 = ["1", "2", "3", "4", "5", "6", "7", "8", "9"]
row9 = ["1", "2", "3", "4", "5", "6", "7", "8", "9"]

random.shuffle(row1)

The two following, smaller (9x3) attempts are equivalent. The first uses the specific index numbers, while the second uses a variable and range to iterate the process instead. They both seem to function fine, without having any element of the list sequence duplicating any other.

# Random Nonduplicate Sequence Generator 1
print("\n")

while row2[0] == row1[0] or row2[1] == row1[1] or row2[2] == row1[2] or row2[3] == row1[3] or row2[4] == row1[4] or row2[5] == row1[5] or row2[6] == row1[6] or row2[7] == row1[7] or row2[8] == row1[8]:
  random.shuffle(row2)

while (row3[0] == row1[0] or row3[1] == row1[1] or row3[2] == row1[2] or row3[3] == row1[3] or row3[4] == row1[4] or row3[5] == row1[5] or row3[6] == row1[6] or row3[7] == row1[7] or row3[8] == row1[8]) or (row3[0] == row2[0] or row3[1] == row2[1] or row3[2] == row2[2] or row3[3] == row2[3] or row3[4] == row2[4] or row3[5] == row2[5] or row3[6] == row2[6] or row3[7] == row2[7] or row3[8] == row2[8]):
  random.shuffle(row3)

print(row1)
print(row2)
print(row3)

# Random Nonduplicate Sequence Generator 2
print("\n")

for x in range(0, 8):

  while row2[x] == row1[x] or row2[x] == row3[x]:
    random.shuffle(row2)

  while row3[x] == row1[x] or row3[x] == row2[x]:
    random.shuffle(row3)

print(row1)
print(row2)
print(row3)

However, when I attempt to expand upon this to encompass a whole 9x9 "grid", I start getting duplicates:

# Random Nonduplicate 9x9 Generator 1
print("\n")
for x in range(0, 8):
  
  while row2[x] == row1[x] or row2[x] == row3[x] or row2[x] == row4[x] or row2[x] == row5[x] or row2[x] == row6[x] or row2[x] == row7[x] or row2[x] == row8[x] or row2[x] == row9[x]:
    random.shuffle(row2)
    
  while row3[x] == row1[x] or row3[x] == row2[x] or row3[x] == row4[x] or row3[x] == row5[x] or row3[x] == row6[x] or row3[x] == row7[x] or row3[x] == row8[x] or row3[x] == row9[x]:
    random.shuffle(row3)

  while row4[x] == row1[x] or row4[x] == row2[x] or row4[x] == row3[x] or row4[x] == row5[x] or row4[x] == row6[x] or row4[x] == row7[x] or row4[x] == row8[x] or row4[x] == row9[x]:
    random.shuffle(row4)

  while row5[x] == row1[x] or row5[x] == row2[x] or row5[x] == row3[x] or row5[x] == row4[x] or row5[x] == row6[x] or row5[x] == row7[x] or row5[x] == row8[x] or row5[x] == row9[x]:
    random.shuffle(row5)

  while row6[x] == row1[x] or row6[x] == row2[x] or row6[x] == row3[x] or row6[x] == row4[x] or row6[x] == row5[x] or row6[x] == row7[x] or row6[x] == row8[x] or row6[x] == row9[x]:
    random.shuffle(row6)
    
  while row7[x] == row1[x] or row7[x] == row2[x] or row7[x] == row3[x] or row7[x] == row4[x] or row7[x] == row5[x] or row7[x] == row6[x] or row7[x] == row8[x] or row7[x] == row9[x]:
    random.shuffle(row7)

  while row8[x] == row1[x] or row8[x] == row2[x] or row8[x] == row3[x] or row8[x] == row4[x] or row8[x] == row5[x] or row8[x] == row6[x] or row8[x] == row7[x] or row8[x] == row9[x]:
    random.shuffle(row8)

  while row9[x] == row1[x] or row9[x] == row2[x] or row9[x] == row3[x] or row9[x] == row4[x] or row9[x] == row5[x] or row9[x] == row6[x] or row9[x] == row7[x] or row9[x] == row8[x]:
    random.shuffle(row9)
  
print(row1)
print(row2)
print(row3)
print(row4)
print(row5)
print(row6)
print(row7)
print(row8)
print(row9)

Is the problem in the for loop iteration or in the while loop logic? Thanks for any insights and assistance.

Adude Andacat
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  • 3
  • `x in range(0, 8)` should be `x in range(9)`, the last value is exclusive. But you can just compare lists using `row1 == row2` – Nick Jun 08 '22 at 00:49
  • https://docs.python.org/3/library/stdtypes.html#typesseq-range – Nick Jun 08 '22 at 00:50
  • @Nick -- The change in range didn't change the outcome, from what I've seen. However, I can compare the two lists as not being the same, yes, but between all lists generated none can have the same value in the same index location. It's enough to satisfy "not the same" when just a single digit is different. When the lists are stacked to form the appearance of 9x9 grid, there cannot be a repeat. There cannot be the same digit across or "up/down". Comparing lists the usual way is only across. Would it be too much space to add example outputs? – Adude Andacat Jun 08 '22 at 03:14

0 Answers0