python - 使用函数跳出 while 循环

Question

有什么方法可以使用函数来打破无限循环吗？例如，

# Python 3.3.2
yes = 'y', 'Y'
no = 'n', 'N'
def example():
    if egg.startswith(no):
        break
    elif egg.startswith(yes):
        # Nothing here, block may loop again
        print()

while True:
    egg = input("Do you want to continue? y/n")
    example()

这会导致以下错误:

SyntaxError: 'break' outside loop

请解释为什么会发生这种情况以及如何解决这个问题。

Answer 1

就我而言，您不能从 example() 中调用 break，但您可以让它按顺序返回一个值(例如:一个 bool 值)停止无限循环

代码:

yes='y', 'Y'
no='n', 'N'

def example():
    if egg.startswith(no):
        return False # Returns False if egg is either n or N so the loop would break
    elif egg.startswith(yes):
        # Nothing here, block may loop again
        print()
        return True # Returns True if egg is either y or Y so the loop would continue

while True:
    egg = input("Do you want to continue? y/n")
    if not example(): # You can aslo use "if example() == False:" Though it is not recommended!
        break