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.

Deze oefening maakt deel uit van de cursus

Writing Efficient Python Code

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Oefeninstructies

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.

Praktische interactieve oefening

Probeer deze oefening eens door deze voorbeeldcode in te vullen.

# Rewrite the for loop to use enumerate
indexed_names = []
for ____,_____ in ____(names):
    index_name = (i,name)
    indexed_names.append(index_name) 
print(indexed_names)

# Rewrite the above for loop using list comprehension
indexed_names_comp = [(____,____) for i,name in ____(names)]
print(indexed_names_comp)

# Unpack an enumerate object with a starting index of one
indexed_names_unpack = [____(names, ____)]
print(indexed_names_unpack)

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