You have learned about two great Python data structures, lists and dictionaries. Now, we need to know when to use these tools. While both tools store information, they do so in very different ways. Let's compare these two structures so that we can better understand how each structure can be used.
Lists are good to use when we want to keep track of items and need to remember the order of those items. We use a lot of lists in everyday life that meet these criteria.
Some examples of lists are as follows:
- A grocery list with different food items
- A list of song titles in an MP3 player
- A list of fiction book titles that are available in a library
- A list of items that are available for purchase on a website
Each of these things has an order as a desirable characteristic, and items can be added or removed from the lists. If we wanted to write a short program in Python to keep track of our fiction book titles or find songs in an MP3 playlist, a list might be a good place to start.
Lists can be used with loops to do a lot of powerful things. Some of these include making lists that create themselves using loops (yes, really) or making lists from lots of user input. Lists are slower to search because they're automatically searched from the beginning.
A dictionary is more useful when data does not need order but needs to be paired with something else. For example, perhaps you own fiction and nonfiction books, and you want to write a program that stores the title, author, and the genre. Using a dictionary would be better for this task so that you can quickly figure out the author of a book based on its title or for all the fiction books that you own. You can also interact with your dictionary to make changes. Also, dictionaries can be searched very quickly because they do not need to be searched from the beginning.