To Lecture Notes

IT 211 -- Feb 25, 2019

Review Exercises

1. What is a dictionary.
   Ans: It is an aggregate datatype that stores key-value pairs. The key and value are separated with a colon ( : ), the key-value pairs are separated by commas ( , ). The entire dictionary are delimited with curley braces ( { } ). Dictionaries are mutable (changeable).
2. Check the datatype of this dictionary object:
   

   d = {'name': 'Alice', 'gender': 'F', 'age': 11}
   Ans:
   print(type(d))
   # Output:
   <class 'dict'>
   

3. Write a script that prints the gender of the person encoded in the dictionary d. Ans:
   

   print(d['gender'])
   

4. Add the phone number 333/444-5555 to the dictionary d. Ans:
   

   d['phone_number'] = '333/444-5555'
   

5. Write a statement to check if 'age' is included in the dictionary d. Ans:
   

   print('age' in d)
   print('ssn' in d)
   # Output:
   True
   False
   

Project 6

• Look at the Project 6 Description.

Some Examples

• These examples use methods from the sys and shutil modules.
• Look at these examples:
  
       CreateFolders1  CreateFolders2  RenameFiles  MakeBackups  SequenceNumbers

Review Questions

1. Write a script that creates a dictionary from the data in this input file pet-info.txt.
   

   # Initialize dictionary:
   d = { }
   
   # Open input file
   fin = open("pet-info.txt", "r")
   
   # Throw away first line
   fin.readline( )
   
   # Process information from file
   line = fin.readline( )
   while line != "":
       fields = line.split(",")
       key = fields[0].strip( )
       value = fields[1].strip( )
       d[key] = value
       line.readline( )
       
   fin.close( )
   print(d)