前言
while是一种循环模式，当满足条件时进入循环，当条件不满足时跳出循环，for循环用于针对集合中的每个元素都一个代码块，而while循环不断地运行，直到指定的条件不满足为止。
while循环
number = 1
while number <= 5:
print(number)
number += 1
break停止循环
number = 1
while number <= 5:
print(number)
number += 1
if number == 3:
break
continue跳出当前循环
number = 0
while number < 10:
number += 1
if number % 2 == 0:
continue
print(number)
在列表间移动元素
unconfirmed_users = ['alice', 'brian', 'candace']
confirmed_users = []
# 此处对列表对象使用while，当list为空时while判断为False
while unconfirmed_users:
current_user = unconfirmed_users.pop()
confirmed_users.append(current_user)
for confirmed_user in confirmed_users:
print(confirmed_user.title())
删除包含特定值的所有列表元素
pets = ['dog', 'cat', 'dog', 'glodfish', 'cat', 'rabbit', 'cat']
print(pets)
while 'dog' in pets:
pets.remove('dog')
print(pets)
