Class 10 Computer Science — Going through a file line by line

1.The file this loop is given has nothing written in it at all. What does the program print?

f = open("empty.txt", "w")
f.write("")
f.close()
total = 0
f = open("empty.txt", "r")
for line in f:
    total = total + int(line)
f.close()
print(total)

2.The numbers out of this file are collected into a list as they are read. What does the program print?

f = open("data.txt", "w")
f.write("6\n11\n4\n")
f.close()
values = []
f = open("data.txt", "r")
for line in f:
    values.append(int(line))
f.close()
print(values[1])

3.Each of these files is read line by line and its numbers added into a total. Put the files in order of the total each one gives, smallest first.

• "2\n3\n"
• "9\n"
• "1\n1\n1\n1\n"
• "6\n8\n"

4.The numbers saved in this file are added up as the loop meets them. What does the program print?

f = open("marks.txt", "w")
f.write("8\n3\n6\n")
f.close()
total = 0
f = open("marks.txt", "r")
for line in f:
    total = total + int(line)
f.close()
print(total)

5.Only some of these lines reach the total. What does the program print?

f = open("takings.txt", "w")
f.write("5\n40\n8\n30\n")
f.close()
total = 0
f = open("takings.txt", "r")
for line in f:
    if int(line) >= 30:
        total = total + int(line)
f.close()
print(total)

6.A loop over an open file is written as "for line in f:". What does line hold on each trip round?

• a) One character of the file
• b) The number of the line, counting from 0
• c) The whole file, all at once
• d) One line of the file, as a piece of writing

7.A decision inside this loop lets only some of the lines reach the counter. What does the program print?

f = open("sales.txt", "w")
f.write("12\n30\n5\n22\n")
f.close()
big = 0
f = open("sales.txt", "r")
for line in f:
    if int(line) > 20:
        big = big + 1
f.close()
print(big)

8.A program opens a file, goes through it with a line loop, and closes it again. Sort each of these lines of code by how often it runs.