Cfrgtkky

I have a dictionary (studentPerf) which has all of the students in a school, with tuples as keys. I want to count the number of male students and the number of female students in the school, and use this to update the values in a second dictionary. The second dictionary (dictDemGender) has 2 keys, male and female, and 0s as the values. How can I change the 0s in dictDemGender to reflect the number of males and females in the school?

Could I do this with dictionary comprehension?

I've given the first few entries to studentPerf:

studentPerf = {('Jeffery','male','junior'):[0.81,0.75,0.74,0.8],

('Able','male','senior'):[0.87,0.79,0.81,0.81],

('Don','male','junior'):[0.82,0.77,0.8,0.8],

('Will','male','senior'):[0.86,0.78,0.77,0.78],

('John','male','junior'):[0.74,0.81,0.87,0.73]}



#Creates a dictionary with genders as keys and 0s as the values to fill later

dictDemGender = {k:0 for k in genders}



dictDemGender = ?

I did ask a similar question but had diagnosed the problem incorrectly. I previously asked for help with finding an average score. What I actually need is a count of the different key possibilities. I need to be able to do so without any outside packages unfortunately.

Use collections.Counter:

from collections import Counter



studentPerf = {('Jeffery','male','junior'):[0.81,0.75,0.74,0.8],

('Able','male','senior'):[0.87,0.79,0.81,0.81],

('Don','male','junior'):[0.82,0.77,0.8,0.8],

('Will','male','senior'):[0.86,0.78,0.77,0.78],

('John','male','junior'):[0.74,0.81,0.87,0.73]}



print(Counter(x[1] for x in studentPerf))

# Counter({'male': 5})

Or, if you need empty counts also:

gender = {'male': 0, 'female': 0}

gender.update(Counter(x[1] for x in studentPerf))

# {'male': 5, 'female': 0}

Or, using dict.fromkeys() with Counter:

d = {'male', 'female'}

gender = dict.fromkeys(d, 0)

gender.update(Counter(x[1] for x in studentPerf))

# {'female': 0, 'male': 5}

Assuming the expected output is {'male':5, 'female':0}, consider using a Counter.

>>> from collections import Counter

>>> c = Counter(male=0, female=0)

>>> c.update(gen for _, gen, _ in studentPerf)

>>> c

Counter({'female': 0, 'male': 5})

Initializing the two keys with zeros is not really necessary, you could also write

>>> c = Counter(gen for _, gen, _ in studentPerf)

>>> c

Counter({'male': 5})

because Counter lookup defaults to zero for missing keys:

>>> c['female']

0

As I said, I was looking for a solution that did not require outside packages. I know the way I've gone about this is rather cumbersome but this was for a class and the exercise had these requirements. I found a way to count all of the males and females and input those values into the dictDemGender dictionary.

genCounts = ([x[1] for x in list(studentPerf.keys())].count('female'), [x[1] for x in list(studentPerf.keys())].count('male'))

dictDemGender = dict(zip(dictDemGender.keys(), genCounts))