Reading assignment:

• Chapter 4, pages 77-79 (Sets).
• Chapter 5, pages 88-96 (Dictionaries).

To be submitted:

• Save all functions in a file named hw8.py
• Page 99, problem 1
  Function declaration: def histogram(lst):
  Return value: A dictionary mapping each word from the list lst to a string of asterisks representing its frequency.
  Note: Do not use get() in your solution.

  >>> histogram(['abc', 'def', 'ghi', 'abc', 'ghi', 'abc'])
  {'abc': '***', 'ghi': '**', 'def': '*'}
  

• Page 99, problem 2
  Function declaration: def unique(lst):
  Return value: The list lst with all duplicates removed.
  Note: You should use a set as an intermediate data structure for this problem.

  >>> unique(['abc', 'def', 'ghi', 'abc', 'ghi', 'abc'])
  ['abc', 'ghi', 'def']
  

• Write the following additional functions:
  • def wordLengths(words): Given a list of words, return a Dictionary with each word as a key and the length of the word as its value.
  • def fileLengths(files): Given a list of filenames, return a Dictionary with each filename as a key and a tuple containing the number of characters, words, and lines in the file as its value. Feel free to use any appropriate functions from the previous assignment to help.
  • def strings2points(strings): Given a list of strings containing two coordinates separated by a space, return a Dictionary with each of the first numbers as a key and each of the second numbers as its value. Use a dictionary comprehension in your implementation.
  • def splitUp(d): Given any dictionary, return two lists: one containing all the keys, the other containing all the values.
  • def stumble3(width, height): Reimplement stumble2() using a dictionary instead of a two-dimensional list.
• Page 111, problem 9
  Function declaration: def spell_checker(filename):
  Return value: A Set containing all misspelled words from filename.
  
  • Use a set to store the words from the dictionary.
  • Get the dictionary from this URL: http://ozark.hendrix.edu/linux/docs/dict-twl06.txt
  • The following programs are useful guides:
    • dump_url.py loads the words into a set and prints out its contents
    • url_in_order.py loads the words into a list rather than a set; their original ordering is preserved when printed
    • count_url.py counts the words from the downloaded file

Additional problems

• Page 99, 3-7.