In this section, we will be creating a simple currency converter application that will be run from the command line using the free to use Fixer.io API (http://fixer.io) to provide the exchange rates, which are updated daily (which is less frequent than some other paid for APIs, but will be good enough for our use).

This is a JSON API; an example URL is: http://api.fixer.io/latest?base=GBP&symbols=JPY,EUR

This is making a request for the exchange rates to convert British pounds to Euro and Yen and returns data in the format:

{
    "base": "GBP",
    "date": "2015-07-08",
    "rates": {
        "JPY": 186.64,
        "EUR": 1.3941
    }
}

As we will see in the next code, this data can be parsed using the json Python module, which will return the structure of the JSON tree as a nested tree of Python dictionaries.

We will start by importing the required Python modules for this script, which we will save as currency_converter.py:

import urllib2
import json
from string import...