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CBSE AISSCE 2016-2017 Marking Scheme for Computer Science
(Sub Code: 083 Paper Code 91 Outside Delhi)

4 (a) Differentiate between file modes ​r+​ and ​rb+​ with respect to Python. 1

Ans r+ Opens a file for both reading and writing. The file pointer placed at
the beginning of the file.
rb+ Opens a file for both reading and writing in binary format. The file
pointer placed at the beginning of the file.

(1 mark for correct difference )
OR
(½ Mark for each correct use of r+ and rb+)

(b) Write a method in python to read lines from a text file MYNOTES.TXT, and display 2
those lines, which are starting with an alphabet ‘K’.

Ans def display():
file=open('MYNOTES.TXT','r')
line=file.readline()
while line:
if line[0]=='K' :
print line
line=file.readline()
file.close() #IGNORE

(½ Mark for opening the file)
(½ Mark for reading all lines)
(½ Mark for checking condition for line starting with K)
(½ Mark for displaying line)
(c) Considering the following definition of class FACTORY, write a method in 3
Python to search and display the content in a pickled file FACTORY.DAT,
where FCTID is matching with the value ‘105’.

class Factory:
def __init__(self,FID,FNAM):
self.FCTID = FID # FCTID Factory ID
self.FCTNM = FNAM # FCTNM Factory Name
self.PROD = 1000 # PROD Production
def Display(self):
print self.FCTID,":",self.FCTNM,":",self.PROD

Ans import pickle
def ques4c( ):
f=Factory( )
file=open('FACTORY.DAT','rb')
try:
while True:
f=pickle.load(file)
if f.FCTID==105:
f.Display()
except EOF Error:
pass
file.close() #IGNORE
(½ Mark for correct method header)
(½ Mark for opening the file FACTORY.DAT correctly)

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