manipulating-lists/questions.rst
author Puneeth Chaganti <punchagan@fossee.in>
Tue, 19 Oct 2010 14:27:56 +0530
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Objective Questions
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.. A mininum of 8 questions here (along with answers)
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1. Given the list primes, ``primes = [2, 3, 5, 7, 11, 13, 17, 19, 23,
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   29]``, How do you obtain the last 4 primes?
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   Answer: primes[-4:]
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#. Given the list primes, ``primes = [2, 3, 5, 7, 11, 13, 17, 19, 23,
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   29]``, What is the output of ``primes[::5]``?
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   Answer: ``[2, 13]``
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#. Given a list, p, of unknown length, obtain the first 3 (or all, if
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   there are fewer) characters of it. 
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   Answer: p[:3]
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#. The method ``reverse`` reverses a list in-place. True or False?
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   Answer: True
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#. ``reversed`` function reverses a list in-place. True or False?
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   Answer: False
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#. Given the list ``p = [1, 2, 3]``. p[4] produces an IndexError. True
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   or False?
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   Answer: True
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#. Given the list ``p = [1, 2, 3]``. p[:4] produces an IndexError. True
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   or False?
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   Answer: False
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#. Given the list primes, ``primes = [2, 3, 5, 7, 11]``, What is the
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   output of ``primes[::-1]``?
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   Answer: [11, 7, 5, 3, 2]
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#. Given the list primes, ``primes = [2, 3, 5, 7, 11]``, What is the
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   output of ``primes[::-3]``?
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   Answer: [11, 3]
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Larger Questions
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.. A minimum of 2 questions here (along with answers)
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#. Given a list p. Append it's reverse to itself. 
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   Answer::
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      p = p + reversed(p)
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#. Marks is a list containing the roll numbers of students followed by
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   marks. [This is not a recommended way to hold the marks details,
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   but the teacher knows only so much Python!] Now she wants to get
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   the average of the marks. Help her do it. 
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   Answer::
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     marks = [1, 9, 2, 8, 3, 3, 4, 10, 5, 2]
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     average = sum(marks[1::2])/len(marks[1::2])
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