我要做的是有一个2D数组,对于数组中的每个坐标,请询问周围所有其他8个坐标,如果他们存储了1或A。到寻找地雷的扫雷机。
我曾经有这个:
grid = []
for fila in range(10):
grid.append([])
for columna in range(10):
grid[fila].append(0)
#edited
for fila in range (10):
for columna in range (10):
neighbour = 0
for i in range 10:
for j in range 10:
if gird[fila + i][columna + j] == 1
neighbour += 1
但是有些事情不好。我也有打印措施来试图以这种方式找到错误,但我仍然不明白为什么它只会使for循环的一半。所以我更改了第二个循环:
#edited
for fila in range (10):
for columna in range (10):
neighbour = 0
if grid[fila - 1][columna - 1] == 1:
neighbour += 1
if grid[fila - 1][columna] == 1:
neighbour += 1
if grid[fila - 1][columna + 1] == 1:
neighbour += 1
if grid[fila][columna - 1] == 1:
neighbour += 1
if grid[fila][columna + 1] == 1:
neighbour += 1
if grid[fila + 1][columna - 1] == 1:
neighbour += 1
if grid[fila + 1][columna] == 1:
neighbour += 1
if grid[fila + 1][columna + 1] == 1:
neighbour += 1
遇到此错误:
if grid[fila - 1][columna + 1] == 1:
IndexError: list index out of range
看来我无法在网格坐标上添加,但我可以减去。为什么?
python中的有效索引为 -len(grid)
至 len(grid)-1
。正索引正在访问元素,而元素从前面偏移,而后方的元素是负面的。如果索引大于您所看到的len(grid)-1
,则会给出范围错误。除非您获得小于-len(grid)
的索引值,否则减去范围错误不会给您带来范围错误。尽管您不检查下边界,即0(零),它似乎对您有用,因为小负数索引从后端返回值。这是导致邻里结果错误的沉默错误。
如果您要计算偏移,则需要确保您的偏移位于列表的范围内。因此,如果您有10个元素,请不要尝试访问第11个元素。
import collections
grid_offset = collections.namedtuple('grid_offset', 'dr dc')
Grid = [[0 for c in range(10)] for r in range(10)]
Grid_height = len(Grid)
Grid_width = len(Grid[0])
Neighbors = [
grid_offset(dr, dc)
for dr in range(-1, 2)
for dc in range(-1, 2)
if not dr == dc == 0
]
def count_neighbors(row, col):
count = 0
for nb in Neighbors:
r = row + nb.dr
c = col + nb.dc
if 0 <= r < Grid_height and 0 <= c < Grid_width:
# Add the value, or just add one?
count += Grid[r][c]
return count
Grid[4][6] = 1
Grid[5][4] = 1
Grid[5][5] = 1
for row in range(10):
for col in range(10):
print(count_neighbors(row, col), "", end='')
print()
打印:
$ python test.py
0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 1 1 1 0 0
0 0 0 1 2 3 1 1 0 0
0 0 0 1 1 2 2 1 0 0
0 0 0 1 2 2 1 0 0 0
0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0
错误正是它所说的,您需要检查坐标是否适合网格:
0 <= i < 10 and 0 <= j < 10
否则,您正在尝试访问不存在内存中不存在的元素,或者您不是您实际想到的元素 - Python处理负索引,它们从末尾计数。
例如。a[-1]
是最后一个元素,与a[len(a) - 1]
。