countries

Code exercise to build a simple command line tool that fetches the REST countries API.

Prerequisites

• Ruby 3.1.1
• Bundler

Installation

Install dependencies with:

$ bundle install

Problem statement

1. Fetch a list of countries with metadata using the REST countries API.

2. Process and display the data accordingly:

   • List countries in a table
   • Show columns: Name, Region, Area, Population
   • Format the area in square metric miles, without decimals (example, for Norway “125020”)
   • Format the population in millions with one decimal (example, for Norway “5.2”)
   • Input option for visualization: sort by one of name, population or area
   • Summary at the end: Show the population average from all the countries, and also the countries with smallest and biggest area.
   • List languages with the countries that speak it in a table
   • Show columns: Language, Countries[], Population

Solution

I have made a CLI in Ruby that fetches and displays data from REST countries API.

Usage

USAGE
  $ bin/countries [OPTIONS]

OPTIONS
  -f condition value   filter countries by the specified conditions.
                       [conditions: name, region, subregion, lang]

  -s condition         sort countries by `condition` in ascending order.
                       [conditions: name (default), region, area, population]

Examples

• Find countries where German is the official language and sort them by population:

  $ bin/countries -f lang german -s population
  +-------------------------------------------------------------------------------+
  |                               Countries Summary                               |
  +------------------------------+--------+------------+--------------------------+
  | Name                         | Region | Area (mi²) | Population (in millions) |
  +------------------------------+--------+------------+--------------------------+
  | Liechtenstein                | Europe |         61 |                     0.0M |
  | Luxembourg                   | Europe |        998 |                     0.6M |
  | Namibia                      | Africa |     318770 |                     2.5M |
  | Belgium                      | Europe |      11786 |                    11.6M |
  | Germany                      | Europe |     137881 |                    83.2M |
  +------------------------------+--------+------------+--------------------------+
  | Population average           |        |            |                    19.6M |
  +------------------------------+--------+------------+--------------------------+
  | Smallest area: Liechtenstein | Europe |         61 |                     0.0M |
  | Biggest area: Namibia        | Africa | 318770     |                     2.5M |
  +------------------------------+--------+------------+--------------------------+
  

• Find countries whose of their names include 'fr' and sort them by area:

  $ bin/countries -f name fr -s area
  +-----------------------------------------------------------------------------------------+
  |                                    Countries Summary                                    |
  +-------------------------------------+-----------+------------+--------------------------+
  | Name                                | Region    | Area (mi²) | Population (in millions) |
  +-------------------------------------+-----------+------------+--------------------------+
  | Saint Martin                        | Americas  |         20 |                     0.0M |
  | French Polynesia                    | Oceania   |       1608 |                     0.3M |
  | French Southern and Antarctic Lands | Antarctic |       2991 |                     0.0M |
  | France                              | Europe    |     213009 |                    67.4M |
  | Central African Republic            | Africa    |     240534 |                     4.8M |
  | South Africa                        | Africa    |     471442 |                    59.3M |
  +-------------------------------------+-----------+------------+--------------------------+
  | Population average                  |           |            |                    22.0M |
  +-------------------------------------+-----------+------------+--------------------------+
  | Smallest area: Saint Martin         | Americas  |         20 |                     0.0M |
  | Biggest area: South Africa          | Africa    | 471442     |                    59.3M |
  +-------------------------------------+-----------+------------+--------------------------+