Python while 循环

1. 让用户选择何时退出

prompt = "\nTell me something, and I will repeat it back to you:"
prompt += "\nEnter 'quit' to end the program. "

message = ""
while message != 'quit':
    message = input(prompt)
    print(message)

示例输出：

让用户选择何时退出

2. 使用标志

prompt = "\nTell me something, and I will repeat it back to you:"
prompt += "\nEnter 'quit' to end the program. "

action = True

while action:
    message = input(prompt)
    if message == "quit":
        action = False
    else:
        print(message)

示例输出：

使用标志

3. 使用 break 退出循环

prompt = "\nTell me something, and I will repeat it back to you:"
prompt += "\nEnter 'quit' to end the program. "

while True:
    message = input(prompt)
    if message == "quit":
        break
    else:
        print(message)

4. 在循环中使用 continue

current_number = 0
while current_number < 10:
    current_number += 1
    if current_number % 2 == 0:
        continue
    print(current_number)

示例输出：

在循环中使用 continue

5. 在列表之间移动元素

unconfirmed_users = ['alice', 'brian', 'candace']
confirmed_users = []

while unconfirmed_users:
    current_user = unconfirmed_users.pop()
    print("Verifying user: " + current_user.title())
    confirmed_users.append(current_user)

print("\nThe following users have been confirmed:")
for confirmed_user in confirmed_users:
    print(confirmed_user.title())

示例输出：

在列表之间移动元素

6. 删除包含特定值的所有列表元素

pets = ['dog', 'cat', 'dog', 'goldfish', 'cat', 'rabbit', 'cat']
print(pets)
while 'cat' in pets:
    pets.remove('cat')
print(pets)

7. 使用用户输入来填充字典

responses = {}

while True:
    name = input("\nWhat is your name? ")
    response = input("Which mountain would you like to climb someday? ")
    responses[name] = response
    repeat = input("Would you like to let another person respond? (yes/ no) ")
    if repeat == 'no':
        break

print("\n--- Poll Results ---")

for name, response in responses.items():
    print(name + " would like to climb " + response + ".")

示例输出：

使用用户输入来填充字典

本文参考自 《Python 编程：从入门到实践》