Python 如何让用户从有限列表中选择输入？
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How to let the user select an input from a finite list?
提问by Gianni Alessandro
I'm quite new of python and programming, so I'm sorry if it's a "noob question". Anyway, is it possible to ask the selection between multiple choice in python, without a if loop?
我对python和编程很陌生，所以如果这是一个“菜鸟问题”，我很抱歉。无论如何，是否可以在没有 if 循环的情况下在 python 中进行多项选择？
Stupid example:
愚蠢的例子：
print "Do you want to enter the door"
raw_input ("Yes or not")
And the user can only choose between the selection.
而用户只能在选择之间进行选择。
回答by Khopa
If you need to do this on a regular basis, there is a convenient library for this purpose that may help you achieve better user experience easily : inquirer
如果您需要定期执行此操作，有一个方便的库可以帮助您轻松获得更好的用户体验：inquirer
Disclaimer : As far as i know, it won't work on Windows without some hacks.
免责声明：据我所知，如果没有一些黑客攻击，它将无法在 Windows 上运行。
You can install inquirer with pip :
您可以使用 pip 安装查询器：
pip install inquirer
Example 1 : Multiple choices
示例 1：多项选择
One of inquirer's feature is to let users select from a list with the keyboard arrows keys, not requiring them to write their answers. This way you can achieve better UX for your console application.
查询器的功能之一是让用户使用键盘箭头键从列表中进行选择，而不要求他们写下答案。通过这种方式，您可以为您的控制台应用程序实现更好的用户体验。
Here is an example taken from the documentation:
这是从文档中获取的示例：
import inquirer
questions = [
inquirer.List('size',
message="What size do you need?",
choices=['Jumbo', 'Large', 'Standard', 'Medium', 'Small', 'Micro'],
),
]
answers = inquirer.prompt(questions)
print answers["size"]
Example 2 : Yes/No questions :
示例 2：是/否问题：
For "Yes/No" questions such as yours, you can even use inquirer's Confirm :
对于像您这样的“是/否”问题，您甚至可以使用查询者的 Confirm ：
import inquirer
confirm = {
inquirer.Confirm('confirmed',
message="Do you want to enter the door ?" ,
default=True),
}
confirmation = inquirer.prompt(confirm)
print confirmation["confirmed"]
Others useful links :
其他有用的链接：
回答by holdenweb
One possible way to achieve what you appear to require is with a whileloop.
实现您似乎需要的一种可能方法是使用while循环。
print "Do you want to enter the door"
response = None
while response not in {"yes", "no"}:
response = raw_input("Please enter yes or no: ")
# Now response is either "yes" or "no"
回答by toto_tico
For those in Python 3, and that want a non case sensitiveoption:
对于那些在Python 3 中，并且想要一个不区分大小写的选项的人：
def ask_user():
print("Do you want to save?")
response = ''
while response.lower() not in {"yes", "no"}:
response = input("Please enter yes or no: ")
return response.lower() == "yes"
And, if I understand Assignment Expressions(PEP 572) correctly, in Python 3.8you will be able to do this:
而且，如果我正确理解赋值表达式（PEP 572），在Python 3.8 中你将能够做到这一点：
def ask_user():
while r:= input("Do you want to save? (Enter yes/no)").lower() not in {"yes", "no"}:
pass
return r.lower() == "yes"
回答by M.Vanderlee
For an OS agnostic solutions using prompt-toolkit 2 or 3, use questionary
对于使用提示工具包 2 或 3 的操作系统不可知解决方案，请使用 questionary
