Description
CS‐521 Homework Assignment 5
Programming Problems
The following includes concepts taught in Chapter 5
5.1: You are going to ask a user for a text file and then count the number of vowels and consonants in that
file. Write a python program that does the following:
Continually prompts user for a text file to read until a valid file is supplied
Create a function named vc_counter():
o takes the valid file name as an argument
o counts the number of vowels and consonants in the file
o returns a dictionary of the count values, using the keys ‘vowels’ and ‘consonants’
Call vc_counter() and store results to a dictionary object
Print the total vowels and consonants with appropriate descriptions (see example).
Notes:
Only the 26 English letters are counted for this exercise.
For this exercise, vowels are: A E I O U
This program does not have to validate or count non‐English letters
Hints:
This will be a lot easier if you make the text file you are evaluating into upper case first
Don’t forget to close the file that you are reading
Example:
Enter a text file: War and Peace.txt
Total # of vowels in text file: 1,200,004*
Total # of consonants in text file: 2,900,679*
* counts made up for illustration
CS‐521 Homework Assignment 5
4
5.2: Write a python program that does the following:
Create 3 functions with docstring:
1. letter_counts() takes a string as its argument and returns a dictionary of the letters as keys and
frequency counts as values.
2. most_common_letter() takes a string as its argument and returns a list of the most common letter(s).
This function should call letter_counts().
3. string_count_histogram() takes a string as its argument and returns a list of the unique letters, with
each letter being the repeated number of times it appears in the string. This list will then be printed
one element per line (as a histogram).
This function should call letter_counts().
The following code should be after the functions and inside the block if __name__ == ‘__main__’:
Assign a sentence of at least 15 characters into a constant string variable.
Write 3 print statements with appropriate descriptions that use these functions to create output like the
examples.
Notes:
Line 1 is sorted alphabetically and not printed as a dictionary
Line 2 grammatically handles more than one result (‘appear’ vs. ‘appears’)
Histogram is sorted alphabetically
Example Output #1
The string being analyzed is: “WAS IT A RAT I SAW”
1. Letter counts: ‘A’: 4, ‘I’: 2, ‘R’: 1, ‘S’: 2, ‘T’: 2, ‘W’: 2
2. Most frequent letter ‘A’ appears 4 times.
3. Histogram:
AAAA
II
R
SS
TT
WW
Example Output #2
The string being analyzed is: “WWWAS IT A RAT I SAW”
1. Letter counts: ‘A’: 4, ‘I’: 2, ‘R’: 1, ‘S’: 2, ‘T’: 2, ‘W’: 4
2. Most frequent letters: ‘A’, ‘W’ each appear 4 times.
3. Histogram:
AAAA
II
R
SS
TT
WWWW
CS‐521 Homework Assignment 5
5
The following includes concepts taught in Chapter 6
5.3 Write a python program without a function that does the following:
Prompts the user to enter four delimited numbers in one request.
Be sure to tell the user in the prompt what delimiter you are expecting.
Use that input to perform the following calculation:
Multiply the first number by the second number, then add that result to the third number, and finally,
divide the result by the fourth number.
This program MUST NOT CRASH.
To insure this you must validate the input data and calculations:
• Checking the user entered four values
• Appropriately checking for the following errors:
ValueError, ZeroDivisionError, IndexError.
o These must be tested in a single conditional block.
o These tests are the key skill being evaluated for this problem
If there is an error during any validation, the program must:
Print descriptive error messages to the console.
Re‐prompt the user for the four delimited numbers
o There should only be a single input statement for this program.
o The program continues to loop until a valid input is provided
After generating valid calculation results, print output that shows in one line the formula applied, an
equal sign, and the result of the calculation.
Exit the program.
Note:
Remembering to have a very granular testing block
o Unrelated commands should not be inside the test
There can only be one input() in this program
No Example Output provided for this question.
CS‐521 Homework Assignment 5
6
The following includes concepts taught in Chapter 8
5.4: Write a python program that does the following:
Prompt for a file name of text words.
Words can be on many lines with multiple words per line.
Read the file, remove all punctuation (leaving just a space between words), and convert the words to a
list.
Call a function you created called list_to_twice_words(), that takes a list as an argument and returns a
list that contains only words that occurred exactly TWICE in the file.
Print the results of the function with an appropriate description.
Think about everything you must do when working with a file.
Hint:
Consider using the string punctuation attribute
No Example Output provided for this question.
CS‐521 Homework Assignment 5
7
The following includes concepts taught in Chapter 15
5.5: This problem is designed for you to practice recursion in a function using factorials.
A factorial is when you multiply a positive integer by the next lower integer all the way down to 1. A
factorial is represented as #!. So 5! = 5 * 4 * 3 * 2 * 1 = 120.
Also note that 0! = 1
Write a python program that does the following:
Prompt the user to enter a factorial starting integer.
o Make sure it’s valid or reprompt the user
Call your function factorial() that:
o takes the starting integer as its argument
o calculated the factorial using recursion
o returns the value
Call your function factorial2() that calculates the factorial without recursion
Print both values with clear descriptions and formatted with thousand commas.
Where to submit?
Click Assignments in the Navigation Area and then click on the title of the assignment to enter the submission
area and upload the zip file with your response.
