# Python Interview Q&A: Essential Concepts for Beginners

## Python Interview Questions And Answers For Beginners

### Overview

The image provides a summary of common Python interview questions and their corresponding solutions. The questions cover a variety of basic Python topics, useful for beginners preparing for interviews. Each section includes a specific question followed by the Python code that implements the solution. Here is a breakdown of the provided information.

### Questions and Answers

#### Check if list contains integer x

```
l = [3, 4, 3, 5, 2, 111, 5]
print(111 in l) # True
```

**Thoughts:**This simple check utilizes Python’s`in`

keyword to determine if a particular element is present in a list.

#### Find duplicate number in integer list

```
def find_duplicates(elements):
duplicates, seen = set(), set()
for element in elements:
if element in seen:
duplicates.add(element)
seen.add(element)
return list(duplicates)
```

**Explanation:**The function identifies duplicates in a list by using two sets: one for seen elements and one for duplicates. This is efficient due to the quick look-up properties of a set.

#### Check if two strings are anagrams

```
def is_anagram(s1, s2):
return set(s1) == set(s2)
print(is_anagram("elvis", "lives")) # True
```

**Idea:**This function checks if two strings contain the same characters by comparing their sets. Note that this approach does not account for character frequency.

#### Remove all duplicates from list

```
lst = list(range(10)) + list(range(10))
lst = list(set(lst))
print(lst) # [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
```

**Explanation:**This snippet removes duplicates by converting the list to a set, then back to a list. This is a quick way to remove duplicates but does not maintain the original order.

#### Find pairs of integers in list so that their sum is equal to integer x

```
def find_pairs(l, x):
pairs = []
for (i, el1) in enumerate(l):
for (j, el2) in enumerate(l[i+1:]):
if el1 + el2 == x:
pairs.append((el1, el2))
return pairs
```

**Explanation:**The function iterates through each pair of elements in the list to find those pairs whose sum equals a specified value`x`

.

#### Get missing number in [1...100]

```
def get_missing_number(lst):
return set(range(1, lst[len(lst)-1]+1)) - set(lst)
l = list(range(1, 100))
l.remove(50)
print(get_missing_number(l)) # {50}
```

**Thoughts:**This function finds the missing number in a sequence by comparing sets of the expected and actual numbers.

#### Compute the intersection of two lists

```
def intersect(lst1, lst2):
res, lst2_copy = [], lst2[:]
for el in lst1:
if el in lst2_copy:
res.append(el)
lst2_copy.remove(el)
return res
```

**Concept:**The function computes the intersection by checking if elements of the first list are in the second list, and adding those to the result list.

#### Find max and min in unsorted list

```
l = [4, 3, 6, 3, 4, 888, 1, -11, 22, 3]
print(max(l)) # 888
print(min(l)) # -11
```

**Explanation:**The`max`

and`min`

functions are used to find the largest and smallest elements in the list.

#### Reverse string using recursion

```
def reverse(string):
if len(string) <= 1: return string
return reverse(string[1:]) + string[0]
print(reverse("hello")) # olleh
```

**Concept:**This recursive function reverses a string by removing the first character, reversing the rest, and appending the first character at the end.

#### Compute the first n Fibonacci numbers

```
a, b = 0, 1
n = 10
for i in range(n):
print(b)
a, b = b, a + b
# 1, 1, 2, 3, 5, 8, ...
```

**Explanation:**The code uses a simple loop to compute and print the first`n`

Fibonacci numbers.

#### Check if a string is a palindrome

```
def is_palindrome(phrase):
return phrase == phrase[::-1]
print(is_palindrome("anna")) # True
```

**Idea:**This function checks if a string is equal to its reverse to determine if it is a palindrome.

#### Sort list with Quicksort algorithm

```
def qsort(L):
if L == []: return []
return qsort([x for x in L[1:] if x < L[0]]) + L[0:1] + qsort([x for x in L[1:] if x >= L[0]])
lst = [44, 33, 2, 55, 77, 999]
print(qsort(lst))
# [2, 33, 44, 55, 77, 999]
```

**Explanation:**This code snippet sorts a list using the Quicksort algorithm, a divide-and-conquer sorting method.

#### Use list as stack, array, and queue

```
# as a list ...
l = [3, 4, 5, 6]
# as a stack ...
l.append(10) # l = [3, 4, 5, 6, 10]
l.pop() # l = [4, 5, 6]
# as a queue ...
l.insert(0, 5) # l = [5, 4, 5, 6]
l.pop() # l = [5, 4, 5]
```

**Concept:**The same list can be manipulated to behave like a stack or queue, demonstrating Python’s list versatility.

#### Find all permutation of string

```
def get_permutations(w):
if len(w) <=1: return set(w)
smaller = get_permutations(w[1:])
perms = set()
for x in smaller:
for pos in range(0, len(x)+1):
perm = x[:pos] + w[0] + x[pos:]
perms.add(perm)
return perms
print(get_permutations("nan"))
# {'nna', 'ann', 'nan'}
```

**Explanation:**This recursive function generates all permutations of a given string using a set to store and return unique permutations.

**Reference:**

www.geeksforgeeks.org

Top 50+ Python Interview Questions and Answers (Latest 2024)

www.interviewbit.com

Top Python Interview Questions and Answers (2024) - InterviewBit

www.simplilearn.com

Top 147+ Python Interview Questions You Must Know in 2024