Question

Language: Python

Topic: API and JSON

Function name: min_pop_countries

Parameters: region (str), num (int)

Return: list of tuples

Description: You are working on a project for your Demography class and you are tasked with finding the top num most populous countries in a given region . Instead of looking up on the Internet, you decide to apply your CS1301 knowledge of APIs and write a function to solve the problem for you. Develop a function that takes in a region (str) and a num (int), return a list of tuples of the form [(country_name, population), …] for the top num most populous countries in the region. The list of tuples you return must be s orted in descending order of population. If the given region is invalid, return “[region] is not a valid region.”

Test Cases:

>>> aList = min_pop_countries("Oceania", 5)

>>> print(aList)

[('Australia', 24117360), ('Papua New Guinea', 8083700), ('New Zeal and', 4697854), ('Fiji', 867000), ('Solomon Islands', 642000)]

API's and data can be found here:

https://restcountries.eu/

^ Data

Answer 1

I have implemented the code as per requirement. I have provided the code and the screenshot with output. Each step is explained with comments.

Code:

import requests

def bySecond(elem):
'''
Custom function, that returns the 2nd element of the input variable
'''
return elem[1]

def min_pop_countries(region, n):
'''
This function calculates most populous countries in a certain region.
@param: string region, integer n
@return: top n number of most populous countries in region
  
'''
#URL to get the data from
main_url = "https://restcountries.eu/rest/v2/region/"
#list of valid regions
regions = ['africa', 'americas', 'asia', 'europe', 'oceania']
#lowercase the region argument
region = region.lower()
#if argument region is part of valid regions
if region in regions:
full_url = main_url + region #construct full region
data = {} #create empty dictionary
response = requests.get(full_url) #get the data
data = response.json() #store in json format
lst = [] #create empty list
for items in data: #loop through the data
lst.append((items['name'], items['population'])) #get the country name and population
  
lst.sort(key=bySecond, reverse = True) #sort the list by population in reverse
  
return lst[0:5] #return top n countries and population
#if argument region is not part of valid regions print error
else:
errorMsg = region + 'is not a valid region'
return errorMsg
aList = min_pop_countries("Oceania",5)
print(aList)

Screenshot: