12.7. Exercises

  1. Write a program that allows the user to enter a string. It then prints a table of the letters of the alphabet in alphabetical order which occur in the string together with the number of times each letter occurs. Case should be ignored. A sample run of the program might look this this:

    Please enter a sentence: ThiS is String with Upper and lower case Letters.
    a  2
    c  1
    d  1
    e  5
    g  1
    h  2
    i  4
    l  2
    n  2
    o  1
    p  2
    r  4
    s  5
    t  5
    u  1
    w  2
    $
    
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  1. Give the Python interpreter’s response to each of the following from a continuous interpreter session:

    1. >>> d = {'apples': 15, 'bananas': 35, 'grapes': 12}
      >>> d['banana']
      
    2. >>> d['oranges'] = 20
      >>> len(d)
      
    3. >>> 'grapes' in d
      
    4. >>> d['pears']
      
    5. >>> d.get('pears', 0)
      
    6. >>> fruits = d.keys()
      >>> fruits.sort()
      >>> print(fruits)
      
    7. >>> del d['apples']
      >>> 'apples' in d
      

    Be sure you understand why you get each result. Then apply what you have learned to fill in the body of the function below, and add code for the tests indicated:

  1. Write a program called alice_words.py that creates a text file named alice_words.txt containing an alphabetical listing of all the words, and the number of times each occurs, in the text version of Alice’s Adventures in Wonderland. (You can obtain a free plain text version of the book, along with many others, from http://www.gutenberg.org.) The first 10 lines of your output file should look something like this

    Word

    Count

    a

    631

    a-piece

    1

    abide

    1

    able

    1

    about

    94

    above

    3

    absence

    1

    absurd

    2

    How many times does the word, alice, occur in the book? If you are writing this in the activecode window simply print out the results rather than write them to a file.

    f = open('alice.txt', 'r')
    
    count = {}
    
    for line in f:
        for word in line.split():
    
            # remove punctuation
            word = word.replace('_', '').replace('"', '').replace(',', '').replace('.', '')
            word = word.replace('-', '').replace('?', '').replace('!', '').replace("'", "")
            word = word.replace('(', '').replace(')', '').replace(':', '').replace('[', '')
            word = word.replace(']', '').replace(';', '')
    
            # ignore case
            word = word.lower()
    
            # ignore numbers
            if word.isalpha():
                if word in count:
                    count[word] = count[word] + 1
                else:
                    count[word] = 1
    
    keys = count.keys()
    keys.sort()
    
    # save the word count analysis to a file
    out = open('alice_words.txt', 'w')
    
    for word in keys:
        out.write(word + " " + str(count[word]))
        out.write('\n')
    
    print("The word 'alice' appears " + str(count['alice']) + " times in the book.")
    
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  1. What is the longest word in Alice in Wonderland? How many characters does it have?

  1. Here’s a table of English to Pirate translations

    English

    Pirate

    sir

    matey

    hotel

    fleabag inn

    student

    swabbie

    boy

    matey

    madam

    proud beauty

    professor

    foul blaggart

    restaurant

    galley

    your

    yer

    excuse

    arr

    students

    swabbies

    are

    be

    lawyer

    foul blaggart

    the

    th’

    restroom

    head

    my

    me

    hello

    avast

    is

    be

    man

    matey

    Write a function named translator that takes a parameter containing a sentence in English (no punctuation and all words in lowercase) and returns that sentence translated to Pirate.

    For example, the sentence “hello there students” should be translated to “avast there swabbies”.

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