''' Purpose: dataset nuance introduction
'''

best_sellers = [
    [ "Name",                             "Author",           "Language", "Date", "Sales" ],
    [ "Don Quixote",                      "de Cervantes",     "Spanish",  1605,   500000000 ],
    [ "A Tale of Two Cities",             "Dickens",          "English",  1859,   200000000 ],
    [ "The Lord of the Rings",            "Tolkien",          "English",  1954,   150000000 ],
    [ "The Little Prince",                "de Saint-Exupery", "French",   1943,   140000000 ],
    [ "Harry Potter",                     "Rowling",          "English",  1997,   120000000 ],
    [ "The Hobbit",                       "Tolkien",          "English",  1937,   100000000 ],
    [ "And Then There Were None",         "Christie",         "English",  1939,   100000000 ],
    [ "Dream of the Red Chamber",         "Xueqin",           "Chinese",  1754,   100000000 ],
    [ "Alice's Adventures in Wonderland", "Carroll",          "English",  1865,   100000000 ],
]

# print the dataset
for row in best_sellers :
    print( row )

print()

# separate out dataset elements
header = best_sellers[ 0 ]
books = best_sellers[ 1 : ]

# determine Sales column
sales_column = header.index( 'Sales' )

print( 'sales column:', sales_column )

print()

# determine total book solds amongs the top best sellers of all time
total = 0
for book in books :
    sold = book[ sales_column ]
    total = total + sold

billions_of_books = total / 1000000000

print( 'Total sold:', billions_of_books, 'billion' )