Good job! In this lesson, we covered:
- Iterables and iterators and how they differ.
- Using the
iter()funtion to create an iterator. - Using the
next()function to manually iterate over an iterator. - How
forloops use iterables and iterators. - How to write custom iterators by implementing the
__iter__()and__next__()methods. - How to use built-in
itertoolsincludingcount(),chain()andcombinations().
There is much more to discover about iterators, iterables, and itertools! Click the respective links to read more.
Let’s practice these concepts some more!
Instructions
Create a list iterable that contains tuples of (cat_toy, price). The list should be called cat_toys. The tuple should consist of the cat toy name and price following the values in the table:
| Toy | Price |
|---|---|
| laser | 1.99 |
| fountain | 5.99 |
| scratcher | 10.99 |
| catnip | 15.99 |
Using iter(), create an iterator called cat_toy_iterator that retrieves the iterator for cat_toys.
Using four next() statements, print out each value in cat_toy_iterator.
A customer enters and only has $15 to spend on exactly 2 cat toys. They want to know how many combinations of the available toys they can afford, while only getting 2 of them total.
First, import itertools at the top of the module.
Next, above the commented out for loop, create a combinations() iterator called toy_combos to retrieve all combinations of 2 total toys from the cat_toys list.
Uncomment all lines of the for loop.
Each iteration of the for loop gives a tuple that is within toy_combos. The variable toy1 represents index 0 of the tuple (the toy name) and cost_of_toy1 represents index 1 of the tuple (the toy cost). We repeat this to store the toy name and price of toy 2 via variables toy2 and cost_of_toy2.
After the final line within the for loop, check if the price of cost_of_toy1 and cost_of_toy2 is less than or equal to max_money which is the max $15 the customer has to spend. If it is, add the tuple to the options list.
Print the final options list to see what toy combinations the customer can buy with $15.