Modifying Functions in Python

Let's revisit the example with the country information. What happens if the name parameter isn't found in the data?


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# Data
countries_dict = {'USA': (9629091, 331002651), 'Canada': (9984670, 37742154), 
                  'Germany': (357114, 83783942), 'Brazil': (8515767, 212559417), 
                  'India': (3166391, 1380004385)}

# Defining a function
def country_information(d, name):
  print('Country:', name)
  print('Area:', d[name][0], 'sq km')
  print('Population:', round(d[name][1]/1000000, 2), 'MM')

# Testing the function
country_information(countries_dict, 'USA')
country_information(countries_dict, 'Ukraine')

Can we manage this problem? Absolutely, by implementing conditional statements!


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# Data
countries_dict = {'USA': (9629091, 331002651), 'Canada': (9984670, 37742154), 
                  'Germany': (357114, 83783942), 'Brazil': (8515767, 212559417), 
                  'India': (3166391, 1380004385)}

# Modify our function
def country_information_mod(d, name):
  if name not in d.keys():
    print("There is no information about", name)
  else:
    print("Country:", name)
    print("Area:", d[name][0], 'sq km')
    print("Population:", round(d[name][1]/1000000, 2), 'mln')
        
# Testing the function
country_information_mod(countries_dict, "USA")
country_information_mod(countries_dict, "Ukraine")

Note

d.keys() is a method used with dictionaries that produces a list of all keys in the dictionary d. Here, it's utilized to verify whether the name is present in the dictionary's keys.

As demonstrated, the error message in this updated format is more user-friendly. While there are many other potential errors and methods to handle them, they're outside the purview of this course.

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Section 6. Chapter 9