Python 如何安排循环？

我是Python编程新手。我正在尝试制作一个程序，帮助水手们使用方便的公式

S*T=D

我根据答案创建了If语句，如下所示

主要问题：

如何清除此代码

为什么即使输入了正确的答案，如“速度”，我也会收到我用于

其他
的答案？（即，即使用户选择了“速度”，输出仍然表示他没有选择三个选项中的一个）

我如何在程序中加入一个循环，这样如果用户输入了错误的答案，它就会返回到初始问题

谢谢大家!

我尝试在
if
语句之前添加
def（）
，但它不起作用。我还尝试在不同的位置执行
而不是True

name = raw_input("what's your name?")
print 'Hi ' + name + ' you landlubber, you.'
# This will tell me whether we want to find out Speed, time, or distance
answer = raw_input("Do you want to figure out your speed, distance, or   time? Choose one and hit 'Enter'").lower()
# This will determine the response to their choice.
if answer == "speed":
print "You is all about that speed eh?"
if answer == "distance":
print "It's all about the journey, not the destination."
if answer == "time":
print "Time is an illusion, bro."
else:
print "You didn't choose one of the three options"

这是一个很好的问题，答案是您需要使用：
if、elif、elif、else
。您可以有任意多个
elif
，但是Python只会选择其中一个
if、elif、else
块来运行

我还在输入中添加了
.strip（）
，以清除空格

name = raw_input("what's your name?")
print 'Hi ' + name + ' you landlubber, you.'

# This will tell me whether we want to find out Speed, time, or distance
answer = raw_input("Do you want to figure out your speed, distance, or time?   Choose one and hit 'Enter'").lower().strip()

# This will determine the response to their choice.
if answer == "speed":
    print "You is all about that speed eh?"
elif answer == "distance":
   print "It's all about the journey, not the destination."
elif answer == "time":
   print "Time is an illusion, bro."
else:
   print "You didn't choose one of the three options"

一般来说，
if/elif
的长字符串很难维护和读取

更好的方法可能是使用字典将输入映射到输出。然后，所有的输入->响应映射都位于一个易于阅读的位置—它们甚至可以从不同的文件导入。决定说什么的逻辑是一个简单的字典查找。您可以使用
get（）
为值不在字典中的情况提供默认值。例如：

# map input to output:
responses = {
    "speed": "You is all about that speed eh?",
    "distance": "It's all about the journey, not the destination.",
    "time": "Time is an illusion, bro."
}

name = raw_input("what's your name?")
print('Hi ' + name + ' you landlubber, you.')

# This will tell me whether we want to find out Speed, time, or distance
answer = raw_input("Do you want to figure out your speed, distance, or   time? Choose one and hit 'Enter'").lower()

# just lookup the response:
print(responses.get(answer, "You didn't choose one of the three options"))

你的缩进是完全错误的，部分问题可能是由此产生的。非常感谢你的回答。这很有帮助！