Python Dictionary Quiz

Question 1

Question 1:Find the output of the following program:

D = dict() 
for x in enumerate(range(2)): 
	D[x[0]] = x[1] 
	D[x[1]+7] = x[0] 
print(D) 

• A. {0: 1, 7: 0, 1: 1, 8: 0}
• B. {1: 1, 7: 2, 0: 1, 8: 1}
• C. {0: 0, 7: 0, 1: 1, 8: 1}
• D. KeyError

Answer: (C)

enumerate() will return a tuple, the loop will have x = (0, 0), (1, 1). Thus D[0] = 0, D[1] = 1, D[0 + 7] = D[7] = 0 and D[1 + 7] = D[8] = 1. Note: Dictionary is unordered, so the sequence of the key-value pair may differ in each output.

Question 2

Question 2:Find the output of the following program:

D = {1 : 1, 2 : '2', '1' : 1, '2' : 3} 
D['1'] = 2
print(D[D[D[str(D[1])]]]) 

• A. 2
• B. 3
• C. '2'
• D. KeyError

Answer: (B)

Simple key-value pair is used recursively, D[1] = 1, str(1) = ‘1’. So, D[str(D[1])] = D[‘1’] = 2, D[2] = ‘2’ and D[‘2’] = 3.

Question 3

Question 3:Find the output of the following program:

D = {1 : {'A' : {1 : "A"}, 2 : "B"}, 3 :"C", 'B' : "D", "D": 'E'} 
print(D[D[D[1][2]]], end = " ") 
print(D[D[1]["A"][2]]) 

• A. C B
• B. E Key Error
• C. B D
• D. D B

Answer: (B)

Key-Value Indexing is used in the example above. D[1] = {‘A’ : {1 : “A”}, 2 : “B”}, D[1][2] = “B”, D[D[1][2]] = D[“B”] = “D” and D[“D”] = “E”. D[1] = {‘A’ : {1 : “A”}, 2 : “B”}, D[1][“A”] = {1 : “A”} and D[1][“A”][2] doesn’t exists, thus KeyError.

Question 4

Question 4:Find the output of the following program:

D = dict() 
for i in range (3): 
	for j in range(2): 
		D[i] = j 
print(D) 

• A. {0: 0, 1: 0, 2: 0}
• B. {0: 1, 1: 1, 2: 1}
• C. {0: 0, 1: 0, 2: 0, 0: 1, 1: 1, 2: 1}
• D. TypeError: Immutable object

Answer: (B)

1st loop will give 3 values to i 0, 1 and 2. In the empty dictionary, valued are added and overwrited in j loop, for eg. D[0] = [0] becomes D[0] = 1, due to overwriting.

Question 5

Question 5:Find the output of the following program:

D = {1 : [1, 2, 3], 2: (4, 6, 8)} 
D[1].append(4) 
print(D[1], end = " ") 
L = [D[2]]
L.append(10) 
D[2] = tuple(L) 
print(D[2]) 

• A. [1, 2, 3, 4] ((4, 6, 8), 10)
• B. [1, 2, 3, 4] (4, 6, 8, 10)
• C. [1, 2, 3, 4] TypeError: tuples are immutable
• D. [1, 2, 3, 4] [4, 6, 8, 10]

Answer: (A)

In the first part, key-value indexing is used and 4 is appended into the list. As tuples are immutable, in the second part the tuple is converted into a list, and value 10 is added finally then converted back to tuple.

Question 6

Question 6:Find the output of the following program:

a = {i: i * i for i in range(6)} 
print (a) 

• A. Dictionary comprehension doesn’t exist
• B. {0: 0, 1: 1, 2: 4, 3: 9, 4: 16, 5: 25, 6:36}
• C. {0: 0, 1: 1, 4: 4, 9: 9, 16: 16, 25: 25}
• D. {0: 0, 1: 1, 2: 4, 3: 9, 4: 16, 5: 25}

Answer: (D)

The above piece of code written in curly braces generate the whole Dictionary.

Question 7

Question 7:Find the output of the following program:

a ={} 
a.fromkeys(['a', 'b', 'c', 'd'], 98) 
print (a) 

• A. Syntax error
• B. {‘a’:98, ‘b’:98, ‘c’:98, ‘d’:98}
• C. {‘a’:None, ‘b’:None, ‘c’:None.’d’:None}
• D. { }

Answer: (D)

fromkeys() create a new dictionary with keys from the list given to it as an argument and set values of the key, the default value given in it as an argument.

Question 8

Question 8:Find the output of the following program:

dict ={} 
print (all(dict)) 

• A. { }
• B. False
• C. True
• D. An exception is thrown

Answer: (C)

The all() method returns:

• True – If all elements in an iterable are true ot iterable is empty.
• False – If any element in an iterable is false.

Question 9

Question 9:Find the output of the following program:

a = {'geeks' : 1, 'gfg' : 2} 
b = {'geeks' : 2, 'gfg' : 1} 
print (a == b) 

• A. True
• B. False
• C. Error
• D. None

Answer: (B)

If two dictionary are the same it returns true, otherwise it returns false.

Question 10

Question 10:Find the output of the following program: Which of these about a dictionary is false?

• A. The values of a dictionary can be accessed using keys
• B. The keys of a dictionary can be accessed using values
• C. Dictionaries may or may not be ordered
• D. None of the above

Answer: (B)

The values of a dictionary can be accessed using keys but the keys of a dictionary can’t be accessed using values.