Python-如何将字典作为输入

Question

Specs: Python3.3.2

What I intend to do:

Take a dictionary as input and return one as output, but the values are now the keys and vice versa

Question: I believe that I can figure out the key-and-value-switch part. But I don't know how to take a dictionary as input.(and keep the object type as dict )

What I tried:

a = input("Please enter a dictionary: ")
print(a)

Result: {'a':1,'b':2} . BUT :

This turned out to be a string object, as is shown using type(a) and getting <class 'str'> as result.

Answer 1

Everything you input in a terminal, will always be a string! Hence, if you enter a correct dict you have to transform it first by executing the given string like this:

import ast
a = input("Please enter a dictionary: ")
d = ast.literal_eval(a)
print d

However, looking at the comments to your question. I don't think somebody would ask you to parse a dict like that from the commandline. Hence, the task probably wants you to just write up a function to receive a dict and print it out, or probably play with it so you can see the difference between mutables and immutables in python and how they are passed around!

Cheers!