FAQ: Code Challenge: Dictionaries - Unique Values

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This community-built FAQ covers the “Unique Values” exercise from the lesson “Code Challenge: Dictionaries”.

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This exercise can be found in the following Codecademy content:

FAQs on the exercise Unique Values

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2

5 posts were split to a new topic: Solution Sharing

6

2 posts were split to a new topic: Why must an empty list be created?

7

I am so proud of myself, thank you codecademy, I did it and I can do that.
So my working example:

def unique_values(my_dictionary):
  seen_values = []
  for value in my_dictionary.values():
    if value in seen_values:
      continue
    else:
      seen_values.append(value)
  return len(seen_values)
8 
def unique_values(my_dictionary):
  seen_values = []
  for value in my_dictionary.values():
    if value == seen_values:
      continue
    else:
      seen_values.append(value)
  return len(seen_values)

tryna understand why this isn’t working, it seems logical to me.

9

nevermind, i see what i did wrong.

10 
def unique_values(my_dictionary):

  return len(set(my_dictionary.values()))
11

The hint given for this challenge isn’t entirely correct or at least misses out a step.
I did the following which returned the correct output:

def unique_values(my_dictionary):
seen_values =
counter = 0
for value in my_dictionary.values():
if value in seen_values:
continue
if value not in seen_values:
seen_values.append(value)
counter += 1
return counter

As you can see I added in a counter and returned the counter instead of seen_values which gave the correct answer for this challenge.

12

Welcome to the forums!

The hint is correct for this challenge. In fact, it isn’t necessary to use a counter to solve this challenge. Take a look at this snippet of your code.

What you are doing here is you are appending each value to seen_values if it is not already in seen_values. Then, you are incrementing the counter by 1.

Take the following argument: [0, 0, 4, 2, 9, 9]. After your code executes, counter will have a value of 4, since it will increment by one for iterations where 0 (the first time), 4, 2, and 9 (the first time) are the value of value. However, these same values will also be appended to seen_values, meaning the length of seen_values (4) is the same as the value of counter (also 4).

In sum, each time you increment counter by 1, you are also appending an element to seen_values, making len(seen_values) == counter.

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