Python Data Structure Interview Questions

Code:

n=int(input("Enter the number till you want to check: "))
primes = []
for i in range (2, n+1):
    for j in range(2, i):
        if i%j == 0:
            break
    else:
        primes.append(i)
        
print("Prime Numbers: ",primes)        
print("Count of prime numbers: ", len(primes))

Output:

Enter the number till you want to check: 11
Prime Numbers:  [2, 3, 5, 7, 11]
Count of prime numbers:  5

To obtain a list of all the keys in a dictionary, we have to use function keys(). Check below example:

my_dict={'k1':10,'k2':5,'k3':20,'k4':25}
keys_list = []

for key in my_dict.keys():
    keys_list.append(key)

print(keys_list)

Output: ['k1', 'k2', 'k3', 'k4']

Elements in lists maintain their ordering unless they are explicitly commanded to be re-ordered. They can be of any data type, they can all be the same, or they can be mixed. Elements in lists are always accessed through numeric, zero-based indices.

In a dictionary, each entry will have a key and a value, but the order will not be guaranteed. Elements in the dictionary can be accessed by using their key.

Lists can be used whenever you have a collection of items in an order. A dictionary can be used whenever you have a set of unique keys that map to values.

 Below code will output 4. This type of assignment is called Tuple Unpacking.

A = 1, 2, 3, 4
a, b, c, d = A
print(d)

 The pop function removes and returns the last object (or obj) from the list. Here -1 represent last element of the list. Below example will return 5.

my_list = [1, 2, 3, 4, 5]
last_element = my_list.pop(-1)
print(last_element)

 Arrays and lists, in Python, have the same way of storing data. But, arrays can hold only a single data type elements whereas lists can hold any data type elements.

import array as arr

my_array = arr.array('i', [1, 2, 3, 4])
my_list=[1, 'abc', 1.20]

print(my_array)
print(my_list)

 list.reverse(): This function reverses objects of list. For example:

my_list = [1, 3, 5, 6]
list.reverse(my_list)
print(my_list)

Code:

set1 = {14, 5, 9, 31, 12, 77, 67, 8}
set2 = {5}

Answer

set1 = {14, 5, 9, 31, 12, 77, 67, 8}
set2 = {5, 77, 9, 12}
print(set1.intersection(set2))

A mechanism to select a range of items from sequence types like list, tuple, strings etc. is known as slicing. Example:

a = ("a", "b", "c", "d", "e", "f", "g", "h")
x = slice(2)
print(a[x])

Output: ('a', 'b')

Common native data structures in Python are as follows:

• Dictionaries (Mutable)
• Lists (Mutable)
• Sets (Mutable)
• Strings (Immutable)
• Tuples (Immutable)

Strings and tuples are immutable, as their contents can't be altered once they're created.