Python Interview Questions

A comprehensive collection of Python programming interview questions covering fundamental concepts, syntax, and practical applications.

Understand the Problem

Problem Statement

Overview

This is a comprehensive set of Python interview questions designed to test fundamental programming concepts and practical knowledge. The questions cover various aspects of Python including:

Python language fundamentals and history
Core programming concepts (functions, operators, data structures)
File handling and I/O operations
Memory management and namespace
Advanced features (decorators, generators, iterators)
String manipulation and data processing

Each question tests understanding of Python syntax, best practices, and problem-solving approaches.

Constraints

All code examples should be syntactically correct Python 3.x
Answers should demonstrate proper Python coding practices
Time complexity should be considered for algorithmic questions
Memory usage should be efficient for data processing tasks
Code should be readable and well-structured

Examples

Example 1

Input

Question: What is the output of the following code?
list = [12,25,15,65,58,14,5]
odd = 0
for val in even:
    if val%2!=0:
        odd = val
        break
    print(val)
print('odd value found',odd)

Output

2
4
6
8
10
odd value found 11

Explanation

The code demonstrates the break statement in Python. It iterates through a list, prints even numbers, and breaks the loop when it finds the first odd number, then prints that odd number.

Example 2

Input

Question: How to create a Unicode string in Python 3?

Output

In Python 3, strings are Unicode by default. You can create Unicode strings using:
- Direct assignment: text = "Hello"
- Using encode: text.encode('utf-8')
- Using unicode escapes: text = "\u03A9" for Ω

Explanation

Python 3 treats all strings as Unicode by default, unlike Python 2 where you needed explicit unicode() calls. The string type in Python 3 is equivalent to unicode in Python 2.

Example 3

Input

Question: What is the difference between list and tuple in Python?

Output

List is mutable while tuple is immutable.
- List: my_list = [1, 2, 3] - can be modified
- Tuple: my_tuple = (1, 2, 3) - cannot be modified after creation

Explanation

This is a fundamental difference in Python data structures. Lists use square brackets and can be modified (add, remove, change elements), while tuples use parentheses and are fixed once created, making them faster and safer for read-only data.

Solution

#include <stdio.h>
#include <string.h>
#include <stdlib.h>

// Example: String manipulation similar to Python strip() function
void strip_whitespace(char *str) {
    char *end;
    
    // Trim leading whitespace
    while(isspace((unsigned char)*str)) str++;
    
    // Trim trailing whitespace
    if(*str == 0) return;
    
    end = str + strlen(str) - 1;
    while(end > str && isspace((unsigned char)*end)) end--;
    
    // Write new null terminator
    *(end + 1) = 0;
}

// Example: Basic array operations similar to Python list operations
void print_array(int arr[], int size) {
    printf("[");
    for(int i = 0; i < size; i++) {
        printf("%d", arr[i]);
        if(i < size - 1) printf(", ");
    }
    printf("]\n");
}

// Example: Function to find minimum similar to Python min() function
int find_min(int arr[], int size) {
    if(size == 0) return 0;
    
    int min_val = arr[0];
    for(int i = 1; i < size; i++) {
        if(arr[i] < min_val) {
            min_val = arr[i];
        }
    }
    return min_val;
}

int main() {
    // Example usage
    char text[] = "   Hello World   ";
    printf("Original: '%s'\n", text);
    strip_whitespace(text);
    printf("Stripped: '%s'\n", text);
    
    int numbers[] = {5, 2, 8, 1, 9};
    int size = sizeof(numbers) / sizeof(numbers[0]);
    
    printf("Array: ");
    print_array(numbers, size);
    printf("Minimum: %d\n", find_min(numbers, size));
    
    return 0;
}

Time:O(n) - Linear time complexity where n is the length of the input

Space:O(1) - Constant space complexity, only using a few variables regardless of input size

Approach:

This C implementation demonstrates several Python concepts translated to C:

String manipulation: The strip_whitespace() function mimics Python's strip() method by removing leading and trailing whitespace
Array operations: The print_array() function shows how to iterate through and display array elements, similar to printing a Python list
Function implementation: The find_min() function implements the logic of Python's min() built-in function

Key differences from Python:

C requires explicit memory management
Arrays have fixed size determined at compile time
String manipulation requires manual character-by-character processing
No built-in high-level functions like Python provides

Visual Explanation

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