Author Dusty Phillips Reviewers

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]
"The children voted for {} ice cream".format(
Counter(responses).most_common(1)[0][0]
)
)
Presumably, you'd get the responses from a database or by using a complicated 
vision algorithm to count the kids who raised their hands. Here, we hardcode it so 
that we can test the 
most_common
method. It returns a list that has only one element 
(because we requested one element in the parameter). This element stores the name 
of the top choice at position zero, hence the double 
[0][0]
at the end of the call. I 
think they look like a surprised face, don't you? Your computer is probably amazed 
it can count data so easily. It's ancestor, Hollerith's Tabulating Machine for the 1890 
US census, must be so jealous!
Lists
Lists are the least object-oriented of Python's data structures. While lists are, 
themselves, objects, there is a lot of syntax in Python to make using them as painless 
as possible. Unlike many other object-oriented languages, lists in Python are 
simply available. We don't need to import them and rarely need to call methods 
on them. We can loop over a list without explicitly requesting an iterator object, 
and we can construct a list (as with a dictionary) with custom syntax. Further, list 
comprehensions and generator expressions turn them into a veritable Swiss-army 
knife of computing functionality.
We won't go into too much detail of the syntax; you've seen it in introductory tutorials 
across the Web and in previous examples in this book. You can't code Python very 
long without learning how to use lists! Instead, we'll be covering when lists should be 
used, and their nature as objects. If you don't know how to create or append to a list, 
how to retrieve items from a list, or what "slice notation" is, I direct you to the official 
Python tutorial, post-haste. It can be found online at 
http://docs.python.org/3/
tutorial/
.
In Python, lists should normally be used when we want to store several instances of 
the "same" type of object; lists of strings or lists of numbers; most often, lists of objects 
we've defined ourselves. Lists should always be used when we want to store items in 
some kind of order. Often, this is the order in which they were inserted, but they can 
also be sorted by some criteria.
As we saw in the case study from the previous chapter, lists are also very useful 
when we need to modify the contents: insert to or delete from an arbitrary location
of the list, or update a value within the list.
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Python Data Structures