Introducing Python / Chapter12 pdb debugging

capitals.py

def process_cities(filename):
    with open(filename, 'rt') as file:
        for line in file:
            line = line.strip()
            if 'quit' in line.lower():
                return
            country, city = line.split(',')
            city = city.strip()
            country = country.strip()
            print(city.title(), country.title(), sep=',')

if __name__ == '__main__':
    import sys
    process_cities(sys.argv[1])

capitals2.py

def process_cities(filename):
    with open(filename, 'rt') as file:
        for line in file:
            line = line.strip()
            if 'quit' == line.lower():  #changed here
                return
            country, city = line.split(',')
            city = city.strip()
            country = country.strip()
            print(city.title(), country.title(), sep=',')

if __name__ == '__main__':
    import sys
    process_cities(sys.argv[1])

cities1.csv

France, Paris
venezuela,caracas
  LithuniA,vilinius
      quit

cities2.csv

argentina,buenos aires
bolivia,la paz
brazil,brasilia
chile,santiago
colombia,Bogotá
ecuador,quito
falkland islands,stanley
french guiana,cayenne
guyana,georgetown
paraguay,Asunción
peru,lima
suriname,paramaribo
urguay,montevideo
venezuela,caracas
quit