33 lines
1.4 KiB
Markdown
33 lines
1.4 KiB
Markdown
# Exercise 2.2 - Solution
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There is no official solution for this exercise--you need rely on your
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current Python knowledge. However, there are a few tips that can
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help.
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- For problems where you need to determine uniqueness, use a set. Sets aren't allowed to
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have duplicates.
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- If you need to tabulate data, consider using a dictionary that maps keys to a numeric
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count. For example, to count rides on each bus route, you could make a dictionary that
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maps the route name to the total ride count for that route. A `Counter` object from
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`collections` is perfect for this task.
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- If you need to keep data in order or sort data, store it in a list.
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- You can make Python data structures out of almost anything. For
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example, dictionaries of sets, nested dictionaries, etc. You might
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need to do this to answer questions 3 and 4.
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Even though no code is provided, here are some answers to the questions
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so that you can check your work:
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1. How many bus routes exist in Chicago? (Answer: 181)
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2. How many people rode the number 22 bus on February 2, 2011? (Answer: 5055)
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3. What is the total number of rides taken on each bus route? (Answer: for the top three routes, [('79', 133796763), ('9', 117923787), ('49', 95915008)])
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4. What five bus routes had the greatest ten-year increase in ridership from 2001 to 2011? (Answer: [('15', 2732209), ('147', 2107910), ('66', 1612958), ('12', 1612067), ('14', 1351308)])
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[Back](ex2_2.md)
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