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Python Python Collections (2016, retired 2019) Dictionaries Teacher Stats

Dillon Reyna
Dillon Reyna
9,531 Points
Posted by Dillon Reyna
Dillon Reyna
9,531 Points

Why do I keep getting a 'couldn't find num_teachers' error?

.

teachers.py 
def num_teachers(diccio):
    for key in diccio.keys():
        teachers += 1
    return teachers

1 Answer

Katie Wood
Katie Wood
19,141 Points
Katie Wood
Katie Wood
19,141 Points

Hi there,

I believe there may be a syntax error occurring inside the function, which is why it's not picking it up - I see the counting variable there, but it's never initialized - teachers += 1 is the same as teachers = teachers + 1, so it's trying to add something that doesn't have a value yet. If you add one line, you can take this approach and it'll work:

def num_teachers(diccio):
    teachers = 0  #add this line
    for key in diccio.keys():
        teachers += 1
    return teachers

It's also worth noting that you can return the length of the dict in a single line using len(), if you're interested: 

def num_teachers(diccio):
    return len(diccio)