Can I use iteration to create variable names?

[perfringo]

I don't understand why. Seeing a simple example and the kind of traceback that can result might help me understand a bit more.

Simple example. Lets say we have class and want have ledger. Normal way would be to have dictionary but we can to it with separate variables:

john = 'student'
mary = 'student'
sonia = 'teacher'

How could we find out how many students we have? How could we find out names of the students? etc, etc

On the other hand, with dictonaries it's simple:

>>> class_ledger = {'john': 'student', 'maria': 'student', 'sonia': 'teacher'}
>>> len(class_ledger)                                                         # total number of people
3
>>> sum(1 for k, v in class_ledger.items() if v == 'student')                 # number of students
2
>>> print(*(k for k, v in class_ledger.items() if v == 'student'), sep='\n')  # names of students
john
maria
>>> 'maria' in class_ledger                                                   # is maria in a ledger
True
>>> class_ledger.update({'Diego': 'student'})                                 # add new person to class
>>> class_ledger
{'john': 'student', 'maria': 'student', 'sonia': 'teacher', 'Diego': 'student'}