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Exercise

Built-in practice: enumerate()

In this exercise, you'll practice using Python's built-in function enumerate(). This function is useful for obtaining an indexed list. For example, suppose you had a list of people that arrived at a party you are hosting. The list is ordered by arrival (Jerry was the first to arrive, followed by Kramer, etc.):

names = ['Jerry', 'Kramer', 'Elaine', 'George', 'Newman']

If you wanted to attach an index representing a person's arrival order, you could use the following for loop:

indexed_names = []
for i in range(len(names)):
    index_name = (i, names[i])
    indexed_names.append(index_name)

[(0,'Jerry'),(1,'Kramer'),(2,'Elaine'),(3,'George'),(4,'Newman')]

But, that's not the most efficient solution. Let's explore how to use enumerate() to make this more efficient.

Instructions

100 XP
  • Instead of using for i in range(len(names)), update the for loop to use i as the index variable and name as the iterator variable and use enumerate().
  • Rewrite the previous for loop using enumerate() and list comprehension to create a new list, indexed_names_comp.
  • Create another list (indexed_names_unpack) by using the star character (*) to unpack the enumerate object created from using enumerate() on names. This time, start the index for enumerate() at one instead of zero.