Finding a value in a dictionary, not a key

Question

I need the programme to select a random value from the dictionary and ask the user what the key is. The dictionary is a glossary. I want the programme to give the user a definition first.

Answer 1

One way you can approach this is to get a random key from your dictionary first and then simply retrieve the value afterwards. To do this, you can use the random library and then do the following:

import random

glossary = {
    "water": "a transparent, odorless, tasteless liquid, a compound of hydrogen and oxygen",
    "wind": "air in natural motion",
    "fire": "a state, process, or instance of combustion in which fuel or other material is ignited and combined with oxygen"
}

correctAnswers = 0
totalQuestions = len(glossary)
while correctAnswers < totalQuestions:
    # Get a random key and value from the glossary dictionary
    word = random.choice(list(glossary.keys()))
    definition = glossary[word]

    # Present the prompt
    print("The definition is:", definition)
    answer = input("What word is this? ")

    # Determine if answer was correct
    if answer.lower() == word:
        print("Correct!")
        correctAnswers += 1
        del glossary[word]
    else:
        print("Incorrect, try again.")

This will output a random definition from within the glossary and will also give the key that it is mapped by. It will then prompt the user to answer what they think the word is. If they are correct, the definition will be removed from the glossary and another question will be asked if one still exists.

Hopefully this gets you started with what you are trying to do.

Answer 2

Here's what I came up with:

import random
d = {'Key 1':'Value 1', 'Key 2':'Value 2'}
randomKey = random.choice(list(d.keys()))
print(d[randomKey])

A random value is printed. Hope this helps.

Edit: You copied the code wrong, it should read:

random_key = random.choice(list(glossary))
print('Define: ', glossary[random_key])
input('Press return to see the definition')
print(glossary[random_key])

Make sure you have imported random import random

Answer 3

I propose this:

import numpy as np
dict = {"cat" : "a carnivorous mammal (Felis catus) long domesticated as a pet and for catching rats and mice.",
        "dog" : "A domesticated carnivorous mammal (Canis familiaris syn. Canis lupus subsp. familiaris) occurring as a wide variety of breeds, many of which are traditionally used for hunting, herding, drawing sleds, and other tasks, and are kept as pets.",
        "butterfly" : "Any of numerous insects of the order Lepidoptera, having four broad, usually colorful wings, and generally distinguished from the moths by having a slender body and knobbed antennae and being active during the day."}

length_dict = len(dict)
list_values = list(dict.values())
list_keys = list(dict.keys())
while True:
    r = np.random.randint(length_dict)
    print("Define: ")
    print(list_values[r])
    inp = input()
    if inp == list_keys[r]:
        print("Correct")

    else:
        print("Wrong")

Answer 4

You can't. Python doesn't support retrieving keys from a dict by their values, since there's no way to guarantee the values are distinct. However, if you flip them (definition is the key, word is the value) it's much easier to do.

From this answer to a similar question, you can use python's random library, coupled with a bit of data manipulation.

To get a list of the python dictionary's keys, you can use list(yourDict.keys() - then, you can use random.choice() from the random library to get a random key. Finally, you can use this random key as an index to d[] in order to get your result.

import random
d = {'An aquatic animal':'FISH', 'A common pet':'DOG'}
question = random.choice(list(d.keys()))
val = d[question]
print(question)
print(val)

Try it here!

Do note that for the above example, if you really want to store the word as the key, you can set val = random.choice(list(d.keys))) and question = d[val].