Starting Out with Python (4th Edition)
4th Edition
ISBN: 9780134444321
Author: Tony Gaddis
Publisher: PEARSON
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Textbook Question
Chapter 9, Problem 3PE
File Encryption and Decryption
Write a
codes = { 'A' :, '%', 'a' : '9', 'B' : '@', 'b' : '#', etc . . .}
Using this example, the letter A would be assigned the symbol %, the letter a would be assigned the number 9, the letter B would be assigned the symbol @, and so forth. The program should open a specified text file, read its contents, then use the dictionary to write an encrypted version of the file’s contents to a second file. Each character in the second file should contain the code for the corresponding character in the first file.
Write a second program that opens an encrypted file and displays its decrypted contents on the screen.
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Dictionaries:
Given the following dictionary definitions:
Foo = {1:’B’, 2:’D’, 3:’C’, 4:’A’}
Bar = {A:’3’,’B’:1,’C’:2,’D’:4}
Give the resulting value for each of the following expressions:
Foo[Bar[‘A’]]
Foo[Bar[‘B’]]
Bar[Foo[1]]
Bar[Foo[2]]
Use a for loop to display the key/value pairs in the above dictionary, one pair to a line.
*python coding please
This exercise assumes that you have created the Employee class for Programming Question 1.Create a program that stores Employee objects in a dictionary. Use the employee ID numberas the key. The program should present a menu that lets the user perform the following actions:• Look up an employee in the dictionary• Add a new employee to the dictionary• Change an existing employee’s name, department, and job title in the dictionary• Delete an employee from the dictionary• Quit the programWhen the program ends, it should pickle the dictionary and save it to a file. Each time theprogram starts, it should try to load the pickled dictionary from the file. If the file does notexist, the program should start with an empty dictionary
File Encryption and DecryptionWrite a program that uses a dictionary to assign “codes” to each letter of the alphabet. Forexample:codes = { ‘A’ : ‘%’, ‘a’ : ‘9’, ‘B’ : ‘@’, ‘b’ : ‘#’, etc . . .}Using this example, the letter A would be assigned the symbol %, the letter a would beassigned the number 9, the letter B would be assigned the symbol @, and so forth.The program should open a specified text file, read its contents, then use the dictionaryto write an encrypted version of the file’s contents to a second file. Each character in thesecond file should contain the code for the corresponding character in the first file.Write a second program that opens an encrypted file and displays its decrypted contentson the screen.
in phyton
Chapter 9 Solutions
Starting Out with Python (4th Edition)
Ch. 9.1 - An element in a dictionary has two parts. What are...Ch. 9.1 - Which part of a dictionary element must be...Ch. 9.1 - Suppose ' start' : 1472 is an element in a...Ch. 9.1 - Suppose a dictionary named employee has been...Ch. 9.1 - What will the following code display? stuff = {1 :...Ch. 9.1 - Prob. 6CPCh. 9.1 - Suppose a dictionary named inventory exists. What...Ch. 9.1 - What will the following code display? stuff = {1 :...Ch. 9.1 - What will the following code display? stuff = {1 :...Ch. 9.1 - What is the difference between the dictionary...
Ch. 9.1 - Prob. 11CPCh. 9.1 - Prob. 12CPCh. 9.1 - What does the values method return?Ch. 9.2 - Prob. 14CPCh. 9.2 - Prob. 15CPCh. 9.2 - Prob. 16CPCh. 9.2 - After the following statement executes, what...Ch. 9.2 - After the following statement executes, what...Ch. 9.2 - After the following statement executes, what...Ch. 9.2 - After the following statement executes, what...Ch. 9.2 - After the following statement executes, what...Ch. 9.2 - Prob. 22CPCh. 9.2 - After the following statement executes, what...Ch. 9.2 - After the following statement executes, what...Ch. 9.2 - Prob. 25CPCh. 9.2 - Prob. 26CPCh. 9.2 - After the following code executes, what elements...Ch. 9.2 - Prob. 28CPCh. 9.2 - After the following code executes, what elements...Ch. 9.2 - After the following code executes, what elements...Ch. 9.2 - After the following code executes, what elements...Ch. 9.2 - Prob. 32CPCh. 9.3 - Prob. 33CPCh. 9.3 - When you open a file for the purpose of saving a...Ch. 9.3 - When you open a file for the purpose of retrieving...Ch. 9.3 - Prob. 36CPCh. 9.3 - Prob. 37CPCh. 9.3 - Prob. 38CPCh. 9 - You can use the __________ operator to determine...Ch. 9 - You use ________ to delete an element from a...Ch. 9 - The ________ function returns the number of...Ch. 9 - You can use_________ to create an empty...Ch. 9 - The _______ method returns a randomly selected...Ch. 9 - The __________ method returns the value associated...Ch. 9 - The __________ dictionary method returns the value...Ch. 9 - The ________ method returns all of a dictionary's...Ch. 9 - The following function returns the number of...Ch. 9 - Prob. 10MCCh. 9 - Prob. 11MCCh. 9 - This set method removes an element, but does not...Ch. 9 - Prob. 13MCCh. 9 - Prob. 14MCCh. 9 - This operator can be used to find the difference...Ch. 9 - Prob. 16MCCh. 9 - Prob. 17MCCh. 9 - The keys in a dictionary must be mutable objects.Ch. 9 - Dictionaries are not sequences.Ch. 9 - Prob. 3TFCh. 9 - Prob. 4TFCh. 9 - The dictionary method popitem does not raise an...Ch. 9 - The following statement creates an empty...Ch. 9 - Prob. 7TFCh. 9 - Prob. 8TFCh. 9 - Prob. 9TFCh. 9 - Prob. 10TFCh. 9 - What will the following code display? dct =...Ch. 9 - What will the following code display? dct =...Ch. 9 - What will the following code display? dct =...Ch. 9 - What will the following code display? stuff =...Ch. 9 - How do you delete an element from a dictionary?Ch. 9 - How do you determine the number of elements that...Ch. 9 - Prob. 7SACh. 9 - What values will the following code display? (Dont...Ch. 9 - After the following statement executes, what...Ch. 9 - After the following statement executes, what...Ch. 9 - After the following statement executes, what...Ch. 9 - After the following statement executes, what...Ch. 9 - After the following statement executes, what...Ch. 9 - What will the following code display? myset =...Ch. 9 - After the following code executes, what elements...Ch. 9 - Prob. 16SACh. 9 - Prob. 17SACh. 9 - Prob. 18SACh. 9 - After the following code executes, what elements...Ch. 9 - Prob. 20SACh. 9 - Write a statement that creates a dictionary...Ch. 9 - Write a statement that creates an empty...Ch. 9 - Assume the variable dct references a dictionary....Ch. 9 - Assume the variable dct references a dictionary....Ch. 9 - Prob. 5AWCh. 9 - Prob. 6AWCh. 9 - Prob. 7AWCh. 9 - Prob. 8AWCh. 9 - Prob. 9AWCh. 9 - Prob. 10AWCh. 9 - Assume the variable dct references a dictionary....Ch. 9 - Write code that retrieves and unpickles the...Ch. 9 - Course information Write a program that creates a...Ch. 9 - Capital Quiz The Capital Quiz Problem Write a...Ch. 9 - File Encryption and Decryption Write a program...Ch. 9 - Unique Words Write a program that opens a...Ch. 9 - Prob. 5PECh. 9 - File Analysis Write a program that reads the...Ch. 9 - World Series Winners In this chapters source code...Ch. 9 - Name and Email Addresses Write a program that...Ch. 9 - Blackjack Simulation Previously in this chapter...Ch. 9 - Word Index Write a program that reads the contents...
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