We begin in a library, where we want to count book copies. With a small collection, we might be able to tally each one manually. However, as the collection grows, this approach becomes cumbersome and inefficient. A more efficient method uses a HashMap, or a dictionary
in Python.
For a quick illustration, consider this list of colors:
If we count manually, red
appears twice, blue
appears thrice, and green
appears once. We can employ HashMaps for a more efficient counting process.
Simple yet powerful, HashMaps allow us to store and retrieve data using keys. The unique colors in our list act as keys, and the count of each color becomes its corresponding value. Let's demonstrate how we can count elements in our colors
list using a Python dictionary:
When the above code executes, it displays the counts for each color: .
