Lab Exercise 9

Assignment Overview

This lab exercise provides practice with dictionaries of lists and sets in Python.

A. Write a program using Dictionaries of lists

Considerthefilenamedlab9a.py. Giventwofilesnamedexactlycontinents.txtand cities.txt (no error checking of the file name is needed) of continents, countries and cities. Write a program to read continents, countries and their cities, put them in a nested dictionary and print them (no duplicates are allowed, i.e. no continent should have the same country listed twice and no country should have the same city listed twice). You should ignore empty strings. Note that both files will be formatted the same, but some names will be in both files and some names will only be in one file. The file format will be one header line followed by lines that have names (string) separated by some unknown number of spaces. A continent can have multiple countries. A country can have multiple cities. If a country is in the cities.txt file, but not in the continents.txt file, it should be ignored. When displaying the dictionaries, the data should be sorted by Continent, by Country, and by city. See sample output below. For output, use this format string for countries "{:>10s} --> "

Requirements: (1) You must use a nested dictionary (dictionary of lists). The keys for the nested dictionaries are

Continent andCountry. (2) You must use the functions that are provided in the template.

Hints

(1) Use a nested dictionary (string(DictionaryList)) Data_map[ Continent ][ Country ] List of cities

(2) To access the outer dictionary, use the first key, e.g., Data_map[ Continent ] (3) To access the inner dictionary, use the second key, e.g.,

 Data_map[ Continent ][ Country ] 

(4) To access a value in a nested dictionary, you have to use both keys and an Index, e.g

 Data_map[ Continent ][ Country ][ Index `] 

(5) Check if the continent exists before adding the country. If it doesnt, add it to the dictionary. (6) Check if the country exists, before adding the city. If it doesnt, add it to the dictionary. (7) Check if the city exists. If it doesnt, add it to the dictionary.

For example, if continents.txt contains Continent Country

Africa Europe 

Asia Asia Europe Europe Africa Africa 

Tunisia Bulgaria 

China Japan Poland Germany Nigeria Tunisia 

and cities.txt contains

Country City Bulgaria Sofia 

China Japan Tunisia Poland Germany Poland Bulgaria Plovdiv 

Nigeria China Tunisia France Japan 

Abuja Shanghai Tunis Paris Tokyo 

Beijing Tokyo Sousse Warsaw Berlin Poznan 

the output will be:

Africa: Nigeria --> Abuja Tunisia --> Sousse, Tunis 

Asia:China --> Beijing, Shanghai Japan --> Tokyo 

Europe: Bulgaria --> Plovdiv, Sofia 

 Germany --> Berlin Poland --> Poznan, Warsaw 

Demonstrate your completed program to your TA. On-line students should submit the completed program (named lab09a.py) for grading via the Mimir system.

B. Write a program using Dictionaries of sets

Rename your file from Part A to lab9b.py. Given the same problem in part A, modify the program to replace lists with sets, i.e. use a dictionary of sets instead of dictionary of lists.

Requirements: (1) You must use a dictionary of sets.

Hints

(1) You probably will only have to modify the build_map function by replacing list initialization with set initialization and using set methods in place of list methods. (Whether you have to modify the display_map function depends on how you implemented it in Part A.)

Demonstrate your completed program to your TA. On-line students should submit the completed program (named lab09b.py) for grading via the Mimir system.

lab09a.py:

from operator import itemgetter

def build_map( in_file1, in_file2 ): in_file1.readline() in_file2.readline()

#READ EACH LINE FROM FILE 1

# Split the line into two words (based on :) countries_list = line.strip().split() # Convert to Title case, discard whitespace continent = countries_list[0].strip().title() country = countries_list[1].strip().title() # Ignore empty strings if continent != "": # If current continent not in map, insert it # YOUR CODE # insert country (continent is guaranteed to be in map) #YOUR CODE # If current continent not in map, insert it

#READ EACH LINE FROM FILE 2

# Split the line into two words (based on :) cities_list = line.strip().split() # Convert to Title case, discard whitespace country = cities_list[0].strip().title() City = cities_list[1].strip().title() # Ignore empty strings if country != "": # insert city (country is guaranteed to be in map) for continent in data_map: if country in data_map[continent]: # YOUR CODE

def display_map( data_map ): #Modify this code to display a sorted nexted dictionary continents_list = [] #sorted list of the continent keys print("{}:".format(continents)) #continents in continents_list countries_list = [] #sorted list of the countries keys in the continents print("{:>10s} --> ".format(countries),end = '') #countries in countries_list cities = [] #sorted list of the cities #when printing add a comma and a spce after the cities names # if it is the last, don't add a comma and a space. print('{}, '.format(city),end = '') # city in cities print('{}'.format(city)) # city in cities

def open_file():

try: filename = input("Enter file name: ") in_file = open( filename, "r" ) except IOError: print( " *** unable to open file *** " ) in_file = None

return in_file

def main():

# YOUR CODE

in_file1 = open_file() #Continents with countries file: continents.txt in_file2 = open_file() #Countries with cities file: cities.txt

if in_file1 != None and in_file2 != None:

data_map = build_map( in_file1, in_file2 ) # data_map is a dictionary display_map( data_map ) in_file1.close() in_file2.close()

if __name__ == "__main__": main()

Lab Exercise 9 Assignment Overview This lab exercise provides practice with dictionaries of lists and sets in Python A. Write a program using Dictionaries of lists Consider the file named "lab9a.". Given two files named exactly continents. txt and cities.txt (no error checking of the file name is needed) of continents, countries and cities. Write a program to read continents, countries and their cities, put them in a nested dictionary and print them (no duplicates are allowed, i.e. no continent should have the same country listed twice and no country should have the same city listed twice). You should ignore empty strings. Note that both files will be formatted the same, but some names will be in both files and some names will only be in one file. The file format will be one header line followed by lines that have names (string) separated by some unknown number of spaces. A continent can have multiple countries. A country can have multiple cities If a country is in the cities.txt file, but not in the continents.txt file, it should be ignored When displaying the dictionaries, the data should be sorted by Continent, by Country, and by city. See sample output below. For output, use this format string for countries "!: >10s --" Requirements (1) You must use a nested dictionary (dictionary of lists). The keys for the nested dictionaries are Continent and Country (2) You must use the functions that are provided in the template. Hints (1) Use a nested dictionary (string Dictionary List Sousse, Tunis Asia: China--> Beijing, Shanghai Japan -Tokyo Europe: Bulgaria >Plovdiv, Sofia Germany >Berlin Poland -> Poznan, Warsaw Demonstrate your completed program to your TA. On-line students should submit the completed program (named "lab09a.") for grading via the Mimir system. B. Write a program using Dictionaries of sets Rename your file from Part A to "lab9b.py" Given the same problemin part A, modify the program to replace lists with sets, i.e. use a dictionary of sets instead of dictionary of lists. Requirements (1) You must use a dictionary of sets. Hints (1) You probably will only have to modify the build map function by replacing list initialization with set initialization and using set methods in place of list methods. (Whether you have to modify the display map function depends on how you implemented i in Part A.) Demonstrate your completed program to your TA. On-line students should submit the completed program (named "lab09b.py") for grading via the Mimir system. Lab Exercise 9 Assignment Overview This lab exercise provides practice with dictionaries of lists and sets in Python A. Write a program using Dictionaries of lists Consider the file named "lab9a.". Given two files named exactly continents. txt and cities.txt (no error checking of the file name is needed) of continents, countries and cities. Write a program to read continents, countries and their cities, put them in a nested dictionary and print them (no duplicates are allowed, i.e. no continent should have the same country listed twice and no country should have the same city listed twice). You should ignore empty strings. Note that both files will be formatted the same, but some names will be in both files and some names will only be in one file. The file format will be one header line followed by lines that have names (string) separated by some unknown number of spaces. A continent can have multiple countries. A country can have multiple cities If a country is in the cities.txt file, but not in the continents.txt file, it should be ignored When displaying the dictionaries, the data should be sorted by Continent, by Country, and by city. See sample output below. For output, use this format string for countries "!: >10s --" Requirements (1) You must use a nested dictionary (dictionary of lists). The keys for the nested dictionaries are Continent and Country (2) You must use the functions that are provided in the template. Hints (1) Use a nested dictionary (string Dictionary List Sousse, Tunis Asia: China--> Beijing, Shanghai Japan -Tokyo Europe: Bulgaria >Plovdiv, Sofia Germany >Berlin Poland -> Poznan, Warsaw Demonstrate your completed program to your TA. On-line students should submit the completed program (named "lab09a.") for grading via the Mimir system. B. Write a program using Dictionaries of sets Rename your file from Part A to "lab9b.py" Given the same problemin part A, modify the program to replace lists with sets, i.e. use a dictionary of sets instead of dictionary of lists. Requirements (1) You must use a dictionary of sets. Hints (1) You probably will only have to modify the build map function by replacing list initialization with set initialization and using set methods in place of list methods. (Whether you have to modify the display map function depends on how you implemented i in Part A.) Demonstrate your completed program to your TA. On-line students should submit the completed program (named "lab09b.py") for grading via the Mimir system