Assignment 22 — function implementation that manipulate lists

Due before class Friday, March 30

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Module quad.py

• Defines four functions for cleaning up lists of strings. Program quadriga.py performs simple testing of quad.py.

• Observation: none of the function implementations require nested for-loops.

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Suppose the following definitions are in effect below

test1 = ['AbCdE', 'ABCDE', '!"#\'x$&)|}~', '- x -_', 'AAcc', ' ', 'x\n']

test2 = ['\tx X']

test3 = []

test4 = ['a', 'B', 'r', 'A', 'c', 'a', 'D', 'a', 'B', 'r', 'a']

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Function lower( strings )

• Returns a new list whose elements are lower case versions of those in strings.

• Given the above definitions of test1, test2, test3, and test4, the following is the expected invocation results for lower().

lower( test1 ) = ['abcde', 'abcde', '!"#\'x$&)|}~', '- x -_', 'aacc', ' ', 'x\n']

lower( test2 ) = ['\tx x']

lower( test3 ) = []

lower( test4 ) = ['a', 'b', 'r', 'a', 'c', 'a', 'd', 'a', 'b', 'r', 'a']

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Function unique( strings )

• Returns a new version of strings without any duplicate values.

• Given the above definitions of test1, test2, test3, and test4, the following is the expected invocation results for unique().

unique( test1 ) = ['AbCdE', 'ABCDE', '!"#\'x$&)|}~', '- x -_', 'AAcc', ' ', 'x\n']

unique( test2 ) = ['\tx X']

unique( test3 ) = []

unique( test4 ) = ['a', 'B', 'r', 'A', 'c', 'D']

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Function strip( strings )

• Returns a new list whose elements correspond to the elements in strings with leading and trailing extraneous characters (punctuation or whitespace) removed.

• Given the above definitions of test1, test2, test3, and test4, the following is the expected invocation results for strip().

strip( test1 ) = ['AbCdE', 'ABCDE', 'x', 'x', 'AAcc', '', 'x']

strip( test2 ) = ['x X']

strip( test3 ) = []

strip( test4 ) = ['a', 'B', 'r', 'A', 'c', 'a', 'D', 'a', 'B', 'r', 'a']

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Function canonical( strings )

• Returns a new list without duplicates whose elements are lower case versions of those in strings with leading and trailing extraneous characters removed.

• Given the above definitions of test1, test2, test3, and test4, the following is the expected invocation results for canonical().

canonical( test1 ) = ['abcde', 'x', 'aacc', '']

canonical( test2 ) = ['x x']

canonical( test3 ) = []

canonical( test4 ) = ['a', 'b', 'r', 'c', 'd']

 

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