Chapter 10. Lists
A List Is a Sequence
Like a string, a list is a sequence of values. In a string, the values are characters; in a list, they can be any type. The values in a list are called elements or sometimes items.
There are several ways to create a new list; the simplest is to
enclose the elements in square brackets (
The first example is a list of four integers. The second is a list of three strings. The elements of a list don’t have to be the same type. The following list contains a string, a float, an integer, and (lo!) another list:
A list within another list is nested.
A list that contains no elements is called an empty list; you can
create one with empty brackets,
As you might expect, you can assign list values to variables:
>>> cheeses = ['Cheddar', 'Edam', 'Gouda'] >>> numbers = [17, 123] >>> empty =  >>> print cheeses, numbers, empty ['Cheddar', 'Edam', 'Gouda'] [17, 123] 
Lists Are Mutable
The syntax for accessing the elements of a list is the same as for accessing the characters of a string—the bracket operator. The expression inside the brackets specifies the index. Remember that the indices start at 0:
>>> print cheeses Cheddar
Unlike strings, lists are mutable. When the bracket operator appears on the left side of an assignment, it identifies the element of the list that will be assigned.
>>> numbers = [17, 123] >>> numbers = 5 >>> print numbers [17, 5]
The one-eth ...