Peer Instruction: Text Files Multiple Choice Questions¶

Q-1: A program is designed to retrieve some data from a file, process it, and output the revised data to another file. Which of the following functions/methods will not be called in the program?

open
Incorrect! Open will be called to open the file to be read.
A loop or method for reading (e.g. read)
Incorrect! A loop or method for reading is required to read an open file.
write
Incorrect! Write will be called to write text on to another file.
close
Incorrect! Close will be called to after the program is done reading or writing a file.
All should be called
Correct! All these functions/methods will be called by the program.

Q-2: Here are the first few lines from a file- songs.txt:

Songs Chosen this Semester #Game names for the songs #All ridiculously good soundtracks Sep, 17, Chrono Cross Sep, 19, Zelda 3

f refers to this file and has just been opened. What does skip return?

def skip(f):
   line = f.readline()
   line = f.readline()
   while line.startswith('#' ):
      line = f.readline()
   return f.readline()

The first line
Incorrect! Because readline() has been called five times. So skip will return the fifth line.
The second line
Incorrect! Because readline() has been called five times. So skip will return the fifth line.
The third line
Incorrect! Because readline() has been called five times. So skip will return the fifth line.
The fourth line
Incorrect! Because readline() has been called five times. So skip will return the fifth line.
The fifth line
Correct! Because readline() has been called five times. So skip will return the fifth line.

Q-3: Here are the first few lines from a file- songs.txt:

Songs Chosen this Semester #Game names for the songs #All ridiculously good soundtracks Sep, 17, Chrono Cross Sep, 19, Zelda 3

f refers to this file and has just been opened. What does skip return?

def skip(f):
   line = f.readline()
   line = f.readline()
   while line.startswith('#' ):
      line = f.readline()
   return line

The first line
Incorrect! Because line was last assigned to the fourth iteration of readline().
The second line
Incorrect! Because line was last assigned to the fourth iteration of readline().
The third line
Incorrect! Because line was last assigned to the fourth iteration of readline().
The fourth line
Correct! Because line was last assigned to the fourth iteration of readline().
The fifth line
Incorrect! Because line was last assigned to the fourth iteration of readline().