如何跳出嵌套的while循环
如何跳出嵌套的while循环
提问于 2014-04-07 22:13:37
我很难挣脱出循环。这是我的密码
while (True):
if (dem_arr[randx, randy] > -100):
ticker = 0
while stack:
x, y = stack.pop()
mask[x, y] = True
for dx, dy in neighbors:
nx, ny = x + dx, y + dy
print ticker
if (0 <= nx < dem_arr.shape[0] and 0 <= ny < dem_arr.shape[1] and dem_arr[x, y] > -100 and dem_arr[nx, ny] > -100 and not mask[nx, ny] and abs(dem_arr[nx, ny] - dem_arr[x, y]) <= 1): #set elevation differnce
stack.append((nx, ny)) #if point is selected (true) array position gets added to stack and process runs over again
if ((nx, ny) not in counterStack):
counterStack.append((nx, ny))
dem_copy[(nx, ny)] = 8888
if (ticker >= 121):
print 'ticker ticked'
#if in this for loop need to break out of while stack:
else:
ticker += 1
else:
print '!chosen has no data!'
randx = random.randint(0, row-1) #array begins at position 0,0
randy = random.randint(0, col-1)
continue我需要做的是，if (ticker >= 121):被输入，我需要突破while stack:和while(True).，对如何做到这一点有什么想法吗？
回答 3
Stack Overflow用户
回答已采纳
发布于 2014-04-07 22:44:36
一个简单的例子说明了使用函数控制内环的概念：
stack = range(1, 500)
def stack_loop():
ticker = 0
while stack:
x = stack.pop()
# Your implementation here
if ticker >= 121:
print("Ticker ticked")
return True
else:
print("Ticker increased")
ticker += 1
return False
while True:
if stack_loop():
break将内环的逻辑移到外部函数，并使用return语句来控制是否需要脱离主循环。
希望它有帮助:)
编辑：您还可以将整个块移动到函数中，只需从函数中移出return：
stack = range(1, 500)
def main_loop():
while True:
ticker = 0
while stack:
x = stack.pop()
# Your implementation here
if ticker >= 121:
print("Ticker ticked")
return
else:
print("Ticker increased")
ticker += 1
main_loop()Stack Overflow用户
发布于 2014-04-07 22:19:14
一种可能的解决方案是使用变量来跟踪(本例中为breakout)：
while (True):
if (dem_arr[randx, randy] > -100):
ticker = 0
breakout = False
while stack and not breakout:
x, y = stack.pop()
mask[x, y] = True
for dx, dy in neighbors:
nx, ny = x + dx, y + dy
print ticker
if (0 <= nx < dem_arr.shape[0] and 0 <= ny < dem_arr.shape[1] and dem_arr[x, y] > -100 and dem_arr[nx, ny] > -100 and not mask[nx, ny] and abs(dem_arr[nx, ny] - dem_arr[x, y]) <= 1): #set elevation differnce
stack.append((nx, ny)) #if point is selected (true) array position gets added to stack and process runs over again
if ((nx, ny) not in counterStack):
counterStack.append((nx, ny))
dem_copy[(nx, ny)] = 8888
if (ticker >= 121):
print 'ticker ticked'
#if in this for loop need to break out of while stack:
breakout = True
break
else:
ticker += 1
else:
print '!chosen has no data!'
randx = random.randint(0, row-1) #array begins at position 0,0
randy = random.randint(0, col-1)
continueStack Overflow用户
发布于 2014-04-07 22:31:02
考虑一下已经提出的意见。另外，考虑一下while循环。而True:本质上是一个无限循环。您可以从函数中返回到调用方，您可以中断与循环相同的级别，或者用一个表达式替换True，该表达式在适当的条件下启动为True。
编辑:您不再使用Java或C语言编程了。没有必要在"True“旁边加上括号。-或其他条件。
页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/22924087
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