Homework 2

Assignment Instruction

• Create a new Jupyter Notebook file to work on the following questions.

• Run your codes to ensure the output is the same as the expected result of each question.

• Rename your Jupyter Notebook (the .ipynb file) as HW2_<LASTNAME>.ipynb, e.g., HW2_CHEN.ipynb.

• Submit this Jupyter Notebook no later than the deadline posted in the course schedule on Canvas.

1. Create a list of cities

• create a list variable named cities that contains top 20 cities in the world,

• print the variable.

Top 20 largest city in the world

ID	Name	Country	Continent	UN Estimation (2018)	Urban Area
1	Tokyo	Japan	Asia	37,400,068	4,751
2	Delhi	India	Asia	28,514,000	14,272
3	Shanghai	China	Asia	25,582,000	5,436
4	Sao Paulo	Brazil	South America	21,650,000	6,949
5	Mexico City	Mexico	South America	21,581,000	9,017
6	Cairo	Egypt	Africa	20,076,000	9,844
7	Mumbai	India	Asia	19,980,000	22,010
8	Beijing	China	Asia	19,618,000	4,659
9	Dhaka	Bangladesh	Asia	19,578,000	36,928
10	Osaka	Japan	Asia	19,281,000	5,129
11	New York	United States	North America	18,819,000	684
12	Karachi	Pakistan	Asia	15,400,000	14,648
13	Buenos Aires	Argentina	South America	14,967,000	5,033
14	Chongqing	China	Asia	14,838,000	5,378
15	Istanbul	Turkey	Europe	14,751,000	11,135
16	Kolkata	India	Asia	14,681,000	13,830
17	Manila	Philippines	Asia	13,482,000	12,798
18	Lagos	Nigeria	Africa	13,463,000	7,877
19	Rio de Janeiro	Brazil	South America	13,293,000	6,181
20	Tianjin	China	Asia	13,215,000	3,886

# write your code below

Tokyo, Delhi, Shanghai, Sao Paulo, Mexico City, Cairo, Mumbai, Beijing, Dhaka, Osaka, New York, Karachi, Buenos Aires, Chongqing, Istanbul, Kolkata, Manila, Lagos, Rio de Janeiro, Tianjin

2. Calculate the ratio of Asian cities in the list

• create a new list called asian_cities.

• print the variable.

# write your code below

Tokyo, Delhi, Shanghai, Mumbai, Beijing, Dhaka, Osaka, Karachi, Chongqing, Kolkata, Manila, Tianjin

• create two new integer variables to calculate the lengths of cities and asian_cities pectively.

• print the two variables.

20
12

• Define a new variable called ratio

• calculate the ratio by using the two lengths.

# write your code below
  

the ratio is: 0.6

3. Indexing and Selecting for list and string

• Select the 16th item in the cities and assign the value to a new variable city.

• create a new variable, you define its name, that calculates the number of characters in city.

• print both variables.

# write your code below
  

Kolkata
7

• Convert the city variable to upper case and lower case and assign the results to city_upper and city_lower respectively.

• print the two new variables

# write your code below

KOLKATA
kolkata

• obtain the second last (negative index) item of cities.

• assign the value you retrieved to a new variable city2.

• concatenate city and city2 (separate with a whitespace) and print the result.

# write your code below

Kolkata Rio de Janeiro

• Select and print out the middle part of the variable city2, i.e., characters between the two spaces.

• To do this, you must use proper start and end indices.

• Your output should be the same as the following cell.

# write your code below
  

de

• reverse the order of the cities and assign the value to a new variable re_cities.

• print out the value of re_cities.

# write your code below

['Tianjin', 'Rio de Janeiro', 'Lagos', 'Manila', 'Kolkata', 'Istanbul', 'Chongqing', 'Buenos Aires', 'Karachi', 'New York', 'Osaka', 'Dhaka', 'Beijing', 'Mumbai', 'Cairo', 'Mexico City', 'Sao Paulo', 'Shanghai', 'Delhi', 'Tokyo']

4. Tuple

• convert cities to a tuple named cities_tuple.

• print the variable.

# write your code below

('Tokyo', 'Delhi', 'Shanghai', 'Sao Paulo', 'Mexico City', 'Cairo', 'Mumbai', 'Beijing', 'Dhaka', 'Osaka', 'New York', 'Karachi', 'Buenos Aires', 'Chongqing', 'Istanbul', 'Kolkata', 'Manila', 'Lagos', 'Rio de Janeiro', 'Tianjin')

• obtain the top 3 cities from this tuple

• use tuple unpacking to assign the items of the tuple to city_1st, city_2nd, and city_3rd respectively.

• print them out.

Tokyo
Delhi
Shanghai

5. Dictionary, Boolean, and format() function

• create a dictionary called african_cities, where

  • key: the names of the two African cities in the cities

  • value: a list contains two integers population and urban area

ID	Name	Country	Continent	UN Estimation (2018)	Urban Area
6	Cairo	Egypt	Africa	20,076,000	9,844
18	Lagos	Nigeria	Africa	13,463,000	7,877

• print the dictionary out

# write your code below

• use format() function to print the following strings

  • “The population of Cario is 20076000 and its urban area is 9844.”

  • “The population of Lagos is 13463000 and its urban area is 7877.”

• you must substitute the numbers of population and urban area with the corresponding values and indexing in african_cities.

# write your code below

• create two variables cario_den and lagos_den

• calculate densities i.e., \(\frac{population}{urban\;area}\) for each city and stores them in the two variables respectively

• compare the two variables using a comparison operator (print it out),

• which city has a larger population (answer by print statement)?

# write your code below
  

True
Cario has a higher population density.