FILENAME = 'metro_areas.txt'

class MetroArea:

def __init__(self, name, country, pop, pop_change, area):

self.name = name

self.country = country

self.pop = pop

self.pop_change = pop_change

self.area = area

def __repr__(self):

return '{0.name}, {0.country} ({0.pop})'.format(self)

def density(self):

return self.pop / self.area

def load():

metro_areas = []

with open(FILENAME, encoding='utf-8') as text:

for line in text:

if line.startswith('#'):

continue

# Country Name Rank Population Yr_change % Area(km2) Pop/km2

country, name, _, pop, pop_change, _, area, _ = line.split('\t')

pop = float(pop.replace(',', ''))

pop_change = float(pop_change)

area = float(area)

metro_areas.append((name, country, pop, pop_change, area))

return metro_areas

def list(metro_areas):

print('{:^18} {:>6} {:>4} {:>6}'.format('name', 'cc', 'pop', 'chg', 'area'))

for metro in metro_areas:

print('{:18} {:2} {:6.0f} {:4.0f} {:6.0f}'.format(*metro))

def list_instances(metro_areas):

metro_areas = [MetroArea(*fields) for fields in metro_areas]

for metro in metro_areas:

print(metro)

if __name__ == '__main__':

#list(load())

list_instances(load())