loading-data-from-files/questions.rst
author bhanu
Sun, 07 Nov 2010 00:22:22 +0530
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Objective Questions
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.. A mininum of 8 questions here. 
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1. ``loadtxt`` can read data only from a file with one column
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   only. True or False?
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   Answer: False
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#. To read a file with multiple columns, into separate simple
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   sequences, ``loadtxt`` is given the additional argument ______?
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   Answer: ``unpack=True``
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#. We have a file with two columns of data separated by one of the
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   following characters. Which of them doesn't require the delimiter
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   argument to be specified, when using ``loadtxt``. 
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   a. ;
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   #. , 
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   #. :
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   #. [space] 
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   Answer: [space]
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#. Given a file ``data.txt`` with three columns of data separated by
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   spaces, read it into one complex sequence. 
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   Answer: ``x = loadtxt("data.txt")``
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#. Given a file ``data.txt`` with three columns of data separated by
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   spaces, read it into 3 separate simple sequences. 
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   Answer: ``x = loadtxt("data.txt", unpack=True)``
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#. Given a file ``data.txt`` with three columns of data separated by
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   ``:``, read it into one complex sequence. 
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   Answer: ``x = loadtxt("data.txt", delimiter=":")``
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#. Given a file ``data.txt`` with three columns of data separated by
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   ":", read it into 3 separate simple sequences. 
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   Answer: ``x = loadtxt("data.txt", unpack=True, delimiter=":")``
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#. To use the loadtxt command, each row should have the same number of
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   values, T or F ?
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   Answer: True
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Larger Questions
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.. A minimum of 2 questions here. 
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1. What will happen if one of the cells is empty?
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#. Given a file with 3 columns of data but two different delimiters,
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   what do you think will happen?
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#. Read a column with text? 
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#. An input file contains 5 columns of data. Use only the second and fourth
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   columns of data and load into two different variables.
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   [hint: read the documentation, use the argument ``usecols``]
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.. #[bhanu: solutions are not seen to have been included.]