CODEWITHSUNDEEP
pythonpython-3.xdictionarycall
kiasy
kiasy

Reputation: 304

How to call a name from a dictionary in Python 3?

Say that I have the following dictionary:

mydict = {"3322": 4 , "3323": 3 , "3324": 5}

Now say that I want to print "3323" once the the user inputs 3. What I've got so far:

printer = input("please enter a number: ")

Now i'm not sure how to use "printer" to print 3323 once the user inputs 3.

Upvotes: 0

Views: 351

Answers (2)

DJG
DJG

Reputation: 6563

Since you are looking for keys (which must be unique) by their corresponding values (that can be repeated more than once in a dictionary,) it is possible for there to be more than one resulting key that maps to a given value.

Fortunately, we can find all of the keys using a list comprehension:

results = [k for k,v in mydict.items() if v == int(printer)]

And of course you can print them all out like so:

print('\n'.join(results))

This way, all of the keys found will be printed (separated by newlines,) and nothing will be printed if nothing is found.

Upvotes: 1

qwwqwwq
qwwqwwq

Reputation: 7329

First your dictionary is "backwards", ie what you want to use a key is actually stored a value, flip it around with a dictionary comprehension:

mydict = {v:k for (k,v) in mydict.iteritems()}

Then it is best to capture user input in a while loop:

while 1:
    key = input("please enter a number: ")
    try:
        if int(key) in mydict:
            print mydict[int(key)]
            break
        else:
            print "{n} not present!".format(n = key)
    except ValueError:
        print "please enter a number!"

This way if the user messes up they can try again..

Upvotes: 0

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