manipulating-strings/questions.rst
author anand
Thu, 11 Nov 2010 00:03:57 +0530
changeset 472 fcdec2d28c9a
parent 294 64d8bc8b33d4
permissions -rw-r--r--
Checklist OK for `The other kinds of plots`

Objective Questions
-------------------

.. A mininum of 8 questions here (along with answers)

1. Given the list week::

     ["sun", "mon", "tue", "wed", "thu", "fri", "sat"]

   ``"Sun" in week`` returns True or False?

   Answer: False
   
#. Given the string ``s = "palindrome"``, what is returned by s[4:]

   Answer: ``ndrome``

#. Given the string ``s = "palindrome"``, what is returned by s[-4]

   Answer: ``r``

#. Given the string ``s = "palindrome"``, what is returned by s[4::-1]

   Answer: ``nilap``

#. Given the string ``s = "palindrome"``, what is returned by s[-4:]

   Answer: ``rome``

#. Given a string ``s = "this is a string"``, how will you change it
   to ``"this isn't a list"`` ?

   Answer::
   
     s = s.replace("string", "list")
     s = s.replace("is", "isn't")

#. Given a string ``s = "this is a string"``, how will you change it
   to ``"THIS ISN'T A LIST"`` ?

   Answer::
   
     s = s.replace("string", "list")
     s = s.replace("is", "isn't")
     s = s.upper()

#. Given a line from a CSV file (comma separated values), convert it
   to a space separated line. 

   Answer: line.replace(',', ' ')

#. Given the string "F.R.I.E.N.D.S" in s, obtain the "friends".

   Answer: ``s[::2].lower()``

Larger Questions
----------------

.. A minimum of 2 questions here (along with answers)

1. Given the string friends, obtain the string "F.R.I.E.N.D.S". 

   Answer::
   
     s = "friends"
     s = s.upper()
     s_list = list(s)
     ".".join(s_list)

2. Given a string with double quotes and single quotes. Interchange
   all the double quotes to single quotes and vice-versa. [Solve it
   for this particular string. Not a generic one. Solve it for a
   generic string, if you know how to iterate over a list.]

   s = """ "Isn't this a 'simple' task?" "No, it isn't." "Yes! it is." """

   Answer::
   
     s = s.replace('"', '#')
     s = s.replace("'", '"')
     s = s.replace('#', "'")        

   .. depends on ``for`` which is not an LO dependency a generic string. 
   
   For generic string
   Answer:: 

     S = []
     s_list = s.split("'")

     for s_s in s_list:
         S.append(s_s.replace('"', "'"))

     s = '"'.join(S)