如何在 python 中對角循環遍歷二維列表？

Question

如果我有一個 function val) 然后我還需要檢查里面有沒有字母

 iagonally)

Answer 1

如果您的 2D 列表保證是方形的，那么您可以按如下方式進行對角線檢查

def diagnoal_check(board2d, start_row, start_column, goal_row, goal_column, row_increment, column_increment):
    curr_row = start_row
    curr_column = start_column
    while(curr_column < len(board2d) and curr_row < len(board2d) and curr_row >= 0 and curr_column >= 0):
        if(board2d[curr_row][curr_column] == "P"):
            return False
        if(curr_column == goal_column and curr_row == goal_row):
            return True

        curr_column += column_increment
        curr_row += row_increment
    return False

然后更新您的條件代碼如下

x = False
if (abs(currow - newrow) == abs(curcol - newcol)):
    x = True
    if ((curcol < newcol) and (currow > newrow)): #NorthEast
        x = diagnoal_check(board2d, currcol, currow, newcol, newrow, -1, 1)
    elif ((curcol < newcol) and (currow < newrow)): #SouthEast
        x = diagnoal_check(board2d, currcol, currow, newcol, newrow, 1, 1)
    elif ((curcol > newcol) and (currow < newrow)): #SouthWest
        x = diagnoal_check(board2d, currcol, currow, newcol, newrow, 1, -1)
    elif ((curcol > newcol) and (currow > newrow)): #NorthWest
        x = diagnoal_check(board2d, currcol, currow, newcol, newrow, -1, -1)

else:
    x = False
    return x

對於您在標題中的問題，對角循環遍歷列表並不復雜，只是您的用例使它變得更加困難，但通常可以通過以下方式實現：

for i in range(len(your_2d_list)):
   print(your_2d_list[i][i])

Answer 2

由於range(start,stop,step) function，這種方法不需要知道方向，綁定在列表理解中

def validate_move(matrix, cur_row, cur_col, new_row, new_col):
    x = False
    if abs(cur_row - new_row) == abs(cur_col - new_col):
        # Create a mapping of points to analyse
        crossed_points = [
            [x for x in range(cur_row, new_row, 1 if new_row - cur_row >= 0 else -1)],  # list of rows indexes
            [y for y in range(cur_col, new_col, 1 if new_col - cur_col >= 0 else -1)],  # list of columns indexes
        ]
        # Check each crossed point to see if P is present
        for point in range(len(crossed_points[0])):
            if matrix[crossed_points[0][point]][crossed_points[1][point]] == "P":
                x = True
                # Stop the loop because P is found
                break
    else:
        x = False
    return x