Question
What is the relationship between the value returned by len()
and the indexes which can be used to access elements of a list?
Answer
The len()
function returns the number of items in a list. Since list indexes start at 0, the value of len()
represents a value one larger than the last index. This means the valid indexes of a list are any number between 0 and len()
- 1. The len()
function is commonly used with the range()
function. Since range()
by default, returns a list from 0 to one less than the number passed, the len()
of a list can be passed to range()
to generate a valid list of indexes. This is shown in the example below.
examples = ['red', 'green', 'blue', 'orange']
# This will print 4 which is the number of elements in examples.
print(len(examples))
# This will return a list ([0, 1, 2, 3]) which provides indexes to the examples.
for color in range(len(examples)):
print(examples[color])