Grade 10 Computer Science — Writing and reading a file

1.What is read back out of this file is turned into a number before it is used. What does the program print?

f = open("score.txt", "w")
f.write("40")
f.close()
f = open("score.txt", "r")
text = f.read()
f.close()
print(int(text) + 2)

2.A program reads a file of several lines using readlines(). What does readlines() hand back?

• a) A list, with one piece of writing in it for each line of the file
• b) A dictionary, with the line numbers as its keys
• c) A number saying how many lines the file holds
• d) One long piece of writing with the whole file in it

3.What comes back from readlines() is an ordinary list, so a position can be asked for out of it. Which word does this program print?

f = open("names.txt", "w")
f.write("pen\nbag\ncup\n")
f.close()
f = open("names.txt", "r")
lines = f.readlines()
f.close()
print(lines[1])

4.A file holds the single line 12. A program opens it, reads that line and holds on to it. What sort of thing is the program holding?

• a) A number, ready to be added to something straight away
• b) Nothing at all until the file has been closed again
• c) A piece of writing, which has to be turned into a number before it can be added to anything
• d) A list holding the digit 1 and the digit 2

5.Two separate writes go into one opening of the file here. What does the program print?

f = open("list.txt", "w")
f.write("red\n")
f.write("blue\n")
f.close()
f = open("list.txt", "r")
lines = f.readlines()
f.close()
print(len(lines))

6.The same file is opened for writing twice here, and each opening writes something different. How many lines does the file hold when this program has finished?

f = open("log.txt", "w")
f.write("first\n")
f.close()
f = open("log.txt", "w")
f.write("red\nblue\n")
f.close()

7.A program saves some writing into a file and then reads it back. Put these five things in the order they have to happen.

• Write the lines into it
• Open the same file again with "r"
• Open the file with "w"
• Read the lines back out
• Close the file

8.This program saves three pieces of writing and then reads them back as a list. What does it print?

f = open("shades.txt", "w")
f.write("red\ngreen\nblue\n")
f.close()
f = open("shades.txt", "r")
lines = f.readlines()
f.close()
print(len(lines))