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Exercises 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
$
Solution.
x = input("Enter a sentence")

x = x.lower()   # convert to all lowercase

alphabet = 'abcdefghijklmnopqrstuvwxyz'

letter_count = {} # empty dictionary
for char in x:
    if char in alphabet: # ignore any punctuation, numbers, etc
        if char in letter_count:
            letter_count[char] = letter_count[char] + 1
        else:
            letter_count[char] = 1

keys = letter_count.keys()
for char in sorted(keys):
    print(char, letter_count[char])

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:

2.

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 1 .) The first 10 lines of your output file should look something like this

Table 12.7.1.
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.

Solution.
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.")
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.")

3.

What is the longest word in Alice in Wonderland? How many characters does it have?

4.

Here's a table of English to Pirate translations

Table 12.7.2.
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”.

Solution.
def translator(sentence):

  pirate = {}
  pirate['sir'] = 'matey'
  pirate['hotel'] = 'fleabag inn'
  pirate['student'] = 'swabbie'
  pirate['boy'] = 'matey'
  pirate['restaurant'] = 'galley'
  pirate['hello'] = 'avast'
  pirate['students'] = 'swabbies'

  psentence = []
  words = sentence.split()
  for aword in words:
     if aword in pirate:
         psentence.append(pirate[aword])
     else:
         psentence.append(aword)

  return " ".join(psentence)
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