Python语法错误：赋值符号（=）引发的数独代码报错问题

Hey there, let's sort out that syntax error you're hitting in your Sudoku setup code!

What's Causing the Error? #

The = sign in your subgrids = dict(...) line is throwing a syntax error because you incorrectly nested this assignment inside the list comprehension that builds subgridlist. Python doesn't allow assignment statements inside the for clause of a list comprehension, and your logic for building subgridlist was mixed up with the subgrids dictionary definition.

Step-by-Step Fix #

Here's the corrected code with clear explanations:

1. First, we properly define the subgrid row/column blocks (for a 16x16 Sudoku, we split rows/columns into 4x4 chunks).
2. We finish building subgridlist with all three components (columns, rows, subgrids) before defining subgrids.
3. We also add missing initializations for dictionaries like dictionary, value, and prune_domain (since they're referenced later but not initialized in your original code).

def InitialiseSudoku():
    # This function initializes a 16x16 Sudoku grid
    cols = '0123456789ABCDEF'
    rows = 'ABCDEFGHIJKLMNOP'
    
    # Define subgrid blocks (4x4 chunks for 16x16 Sudoku)
    row_blocks = (rows[0:4], rows[4:8], rows[8:12], rows[12:16])
    col_blocks = (cols[0:4], cols[4:8], cols[8:12], cols[12:16])
    
    global coordinates
    coordinates = represent(rows, cols)  # Assume `represent` returns all cell coordinates (e.g., A0, A1, ..., PF)
    
    global subgridlist
    # Build subgridlist: columns, rows, and 4x4 subgrids
    subgridlist = (
        [represent(rows, c) for c in cols]  # All columns (each column's cells)
        + [represent(r, cols) for r in rows]  # All rows (each row's cells)
        + [represent(rs, cs) for rs in row_blocks for cs in col_blocks]  # All 4x4 subgrids
    )
    
    # Now define subgrids (map each cell to its containing subgrids)
    global subgrids
    subgrids = dict((s, [u for u in subgridlist if s in u]) for s in coordinates)
    
    global constraintpartners
    constraintpartners = dict((s, set(sum(subgrids[s], [])) - set([s])) for s in coordinates)
    
    # Initialize missing dictionaries
    global dictionary, value, prune_domain
    dictionary = {}
    value = {}
    prune_domain = {}
    
    # Populate dictionaries (assuming input_list is a predefined list of initial values)
    i = 0
    for s in coordinates:
        dictionary[s] = ['1'] * 16  # Simplified: 16 possible values for 16x16 Sudoku
        value[s] = input_list[i]
        prune_domain[s] = [''] * 17  # Match the length in your original code
        i += 1

Key Notes: #

• I assumed your represent function takes a set of rows/columns and returns all cell coordinates for that group (e.g., represent('ABCD', '0123') returns all cells in the top-left 4x4 subgrid).
• The input_list variable needs to be defined somewhere (it's referenced but not shown in your original code).
• The syntax error is fixed by separating the subgridlist construction and subgrids dictionary definition into two distinct, valid steps.

内容的提问来源于stack exchange，提问作者Frederick