Prerequisite: Dictionary
Note: Output of all these programs is tested on Python3
1.What is the output of the following of code?
a = {i: i * i for i in range(6)}
print (a)
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Options:
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}
Ans. (d)
Explanation: The above piece of code written in curly braces generate the whole Dictionary.
2.What is the output of the following of code?
a ={}
a.fromkeys(['a', 'b', 'c', 'd'], 98)
print (a)
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Options:
a) Syntax error
b) {‘a’:98, ‘b’:98, ‘c’:98, ‘d’:98}
c) {}
d) {‘a’:None, ‘b’:None, ‘c’:None.’d’:None}
Ans. (c)
Explanation:fromkeys() create a new dictionary with keys from list given to it as an argument and set values of the key, the default value given in it as an argument.
Input:
a ={}
dict = a.fromkeys(['a', 'b', 'c', 'd'], 98)
print (a)
print (dict)
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Output:
{}
{'d': 98, 'b': 98, 'a': 98, 'c': 98}
3.What is the output of the following of code?
dict ={}
print (all(dict))
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Options:
a) { }
b) False
c) True
d) An exception is thrown
Ans.(c)
Explanation: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.Input:
a = {}
b = a.fromkeys([1, False, 3], 'True')
print (all(a))
print (all(b))
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Output:
True
False
4.What is the output of the following of code?
a = {'geeks' : 1, 'gfg' : 2}
b = {'geeks' : 2, 'gfg' : 1}
print (a == b)
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a) True
b) False
c) Error
d) None
Ans. (b)
Explanation:If two dictionary are same it returns true, otherwise it returns false.
5.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
Ans.(b)
Explanation: The values of a dictionary can be accessed using keys but the keys of a dictionary can’t be accessed using values.