If you want to build something using a Raspberry Pi, you'll probably use resistors. 
For this exercise, you need to know two things about them:
<ul>
<li>Each resistor has a resistance value.</li>
<li>Resistors are small - so small in fact that if you printed the resistance value on them, it would be hard to read.</li>
</ul>
To get around this problem, manufacturers print color-coded bands onto the resistors to denote their resistance values. 
Each band has a position and a numeric value.
The first 2 bands of a resistor have a simple encoding scheme: each color maps to a single number.
In this exercise you are going to create a helpful program so that you don't have to remember the values of the bands.
These colors are encoded as follows:
<ul>
<li>Black: 0</li>
<li>Brown: 1</li>
<li>Red: 2</li>
<li>Orange: 3</li>
<li>Yellow: 4</li>
<li>Green: 5</li>
<li>Blue: 6</li>
<li>Violet: 7</li>
<li>Grey: 8</li>
<li>White: 9</li>
</ul>
The goal of this exercise is to create a way:
<ul>
<li>to look up the numerical value associated with a particular color band</li>
<li>to list the different band colors</li>
</ul>
Mnemonics map the colors to the numbers, that, when stored as an array, happen to map to their index in the array: 
Better Be Right Or Your Great Big Values Go Wrong.
More information on the color encoding of resistors can be found in the <a href="https://en.wikipedia.org/wiki/Electronic_color_code" target="_blank" rel="noopener nofollow">Electronic color code Wikipedia article</a>.

Resistor Color