BS Degree Assignment Solutions & Study Resources - IIT Madras

Week-2, Practice

This document has 13 questions.

Question-1

Statement

Which of the following are valid names for variables in Python? (MSQ)

Options

• (a) a_
• (b) _a
• (c) 1a
• (d) a variable
• (e) a_variable

Answer

(a), (b), (e)

Hint

Rules for variable names in Python:

• A variable name can contain only alpha-numeric characters and underscores (A-Z, a-z, 0-9, and _).
• A variable name must start with a letter or the underscore character.

Question-2

Statement

Execute the following code-block. Assume that word1 and word2 are strings that have already been defined.

# word1, word2 are two strings
print(word1 + word2)
word = word1
word1 = word2
word2 = word
print(word2 + word1)
        

Select the statement that accurately describes the two lines in the output.

Options

• (a) The two lines are always the same.
• (b) The two lines are always different.
• (c) The two lines are the same if and only if word1 and word2 are equal.
• (d) None of the above

Answer

(a)

Hint

Lines 3-5 swap the values of variables word1 and word2 using a temporary variable word.

Question-3

Statement

Assume that a, b, and c are three distinct integers. The following code runs without any error.

x, y, z = a, b, c
x = y = z
        

Select all statements that evaluate to True at the end of execution of the code given above. (MSQ)

Options

• (a) x == y == z
• (b) x == y == z == a
• (c) x == y == z == b
• (d) x == y == z == c

Answer

(a), (d)

Hint

After the first line, x = a, y = b, and z = c. Then, after the second line, all variables are assigned the value of c.

Question-4

Statement

x is a variable of type float and is of the form a.bcd, where a, b, c, d are all positive integers less than 10. What is the output of the following snippet of code?

print(int(x))
print(int(-x))
        

Options

• (a) a a
• (b) a + 1 a + 1
• (c) a - 1 a - 1
• (d) a - 1 -a
• (e) a -a + 1
• (f) a -a

Answer

(f)

Hint

int(x) retains the integer part and removes the fractional part.

Question-5

Statement

Consider the following code blocks:

# Block-1
flag = True
if flag == True:
    print('works')

# Block-2
flag = True
if flag:
    print('works')
        

Are the two blocks equivalent?

Options

• (a) Yes
• (b) No

Answer

(a)

Hint

Both blocks are equivalent. However, it's recommended to use the second form: if flag rather than if flag == True.

Question-6

Statement

Consider the following code-blocks. E is a Boolean expression. Two blocks of code are said to be equivalent if they produce the same output for a given input.

# Block-1
if E:
    print('good')
else:
    print('bad')

# Block-2
if E:
    print('good')
print('bad')

# Block-3
print('good')
print('bad')
        

Select all true statements. (MSQ)

Options

• (a) All three blocks are equivalent to each other.
• (b) Exactly two of these three blocks are equivalent to each other.
• (c) Block-1 and Block-2 are equivalent.
• (d) Block-1 and Block-3 are equivalent.

Answer

(b), (c)

Hint

Block-2 always prints both messages, while Block-1 only prints one message depending on the value of E.