previous key and next value access in Dictionary

Question

#Write a function called rabbit_hole. rabbit_hole should have two parameters: a #dictionary and a string. The string may be a key to the dictionary. The value associated #with that key, in turn, may be another key to the dictionary. Keep looking up the keys #until you reach a key that has no associated value. Then, return that key.
#For example, imagine if you had the following dictionary. This one is sorted to make this example easier to follow:
# d = {"bat": "pig", "pig": "cat", "cat": "dog", "dog": "ant",
# "cow": "bee", "bee": "elk", "elk": "fly", "ewe": "cod",
# "cod": "hen", "hog": "fox", "fox": "jay", "jay": "doe",
# "rat": "ram", "ram": "rat"}
#If we called rabbit_hole(d, "bat"), then our code should...
# - Look up "bat", and find "pig"
# - Look up "pig", and find "cat"
# - Look up "cat", and find "dog"
# - Look up "dog", and find "ant"
# - Look up "ant", and find no associated value, and so it would
# return "ant".
#Notice that if the initial string passed in is not a key in the dictionary, that string should be returned as the result as well.
#Note, however, that it is possible to get into a loop. In the dictionary above, rabbit_hole(d, "rat") would infinitely go around between "rat" and "ram". You should prevent this: if a key is ever accessed more than once (meaning a loop has been
#reached), return the boolean False.
#Hint: If you try to access a value from a dictionary that does
#not exist, a KeyError will be raised.
#Write your function here!
def rabbit_hole(myDict, mystring):
get_string = mystring
try:
for key, value in myDict.items():
if get_string in myDict.keys() :
get_string = myDict[get_string]
else:
return get_string
except KeyError:
return False
print(rabbit_hole(d, "rat"))
print(rabbit_hole(d, "yak"))

I am getting the right answer for 'yak' but not for 'rat' since it is looping. Can anyone help me fix it.

Answer 1

Good thing you leave the parameter mystring untouched. After setting get_string in the loop you can compare get_string to mystring and return or raise an error if equal

Answer 2

You can delete the if statement and use the try except instead (return get_string instead of False)

Answer 3

if part leading to wrong.. According to question, you shloud try get_string = myDict[get_string] if it raise error, then return values where it stopped otherwise return value at loop end..

Answer 4

Thank you Benjamin Jürgens and Jayakrishna🇮🇳 for your input. It works now.