Topic 3 - Persistence & Inheritance

Question 1

File Input and Output

Answer 1

The process of opening a file, processing it by writing or reading data, and closing the file

Question 1

Persistence

Answer 1

The ability of a program to save data for later use

Question 2

Binary files

Answer 2

Data not encoded as text, not human readable

Question 3

Text files

Answer 3

Data encoded as text as a series of characters, human readable

Question 4

Sequential Access

Answer 4

Accessing data from the beginning of the file to the end of the file

Question 5

Direct Access

Answer 5

Jumping directly to any piece of data in the file without reading the data that comes before it

Question 6

File object

Answer 6

An object associated with a specific file that provides a way for the program to work with the file

Question 7

Open() function

Answer 7

Used to open a file, given its file name and the operation mode

Question 8

‘r’ mode

Answer 8

Read mode, file cannot be changed

Question 9

‘w’ mode

Answer 9

Write mode, new file will be created

Question 10

‘a’ mode

Answer 10

Append mode, data will be appended to the end of the file

Question 11

write() method

Answer 11

Used to write a string to the file

Question 12

close() method

Answer 12

Used to close the file object

Question 13

read() method

Answer 13

Used to read the entire content from the file

Question 14

readline() method

Answer 14

Used to read line by line from the file

Question 15

Detecting End of File

Answer 15

Calling readline() before entering a while loop to test for empty string, or using a for loop

Question 16

Shelve

Answer 16

Python object persistence, a dictionary-like object for persistent storage

Question 17

shelve.open()

Answer 17

Used to open a persistent storage for reading and writing, creating it if it doesn’t exist

Question 18

db[‘key’]

Answer 18

Used to store and retrieve data in the underlying database

Question 19

db.close()

Answer 19

Used to close the underlying database when it is not in use

Question 20

Exception

Answer 20

An error that occurs while a program is running

Question 21

try/except statement

Answer 21

Used to handle exceptions gracefully

Question 22

else clause

Answer 22

Executed if no exceptions are raised

Question 23

finally clause

Answer 23

Ensures that certain code is always executed, regardless of whether an exception is raised or not