Python Data Science Jobs & Interviews
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Your go-to hub for Python and Data Scienceβ€”featuring questions, answers, quizzes, and interview tips to sharpen your skills and boost your career in the data-driven world.

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Python Question / Quiz;

What is the output of the following Python code, and why? πŸ€”πŸš€ Comment your answers below! πŸ‘‡

#python #programming #developer #programmer #coding #coder #softwaredeveloper #computerscience #webdev #webdeveloper #webdevelopment #pythonprogramming

https://t.iss.one/DataScienceQ
πŸ‘2❀1
What will be the output of the following code?

import numpy as np
numbers = np.array([1, 2, 3])
new_numbers = numbers + 1
print(new_numbers.tolist())


#python #programming #developer #programmer #coding #coder #softwaredeveloper #computerscience #webdev #webdeveloper #webdevelopment #pythonprogramming

https://t.iss.one/DataScienceQ
πŸ‘2
Python Question / Quiz;

What is the output of the following Python code, and why? πŸ€”πŸš€ Comment your answers below! πŸ‘‡

#python #programming #developer #programmer #coding #coder #softwaredeveloper #computerscience #webdev #webdeveloper #webdevelopment #pythonprogramming #pythonquiz #ai #ml #machinelearning #datascience

https://t.iss.one/DataScienceQ
πŸ‘3
Python Question / Quiz;

What is the output of the following Python code, and why? πŸ€”πŸš€ Comment your answers below! πŸ‘‡

#python #programming #developer #programmer #coding #coder #softwaredeveloper #computerscience #webdev #webdeveloper #webdevelopment #pythonprogramming

https://t.iss.one/DataScienceQ
πŸ‘2
🧠 What is a Generator in Python?
A generator is a special type of iterator that produces values lazilyβ€”one at a time, and only when neededβ€”without storing them all in memory.

---

❓ How do you create a generator?
βœ… Correct answer:
Option 1: Use the yield keyword inside a function.

πŸ”₯ Simple example:

def countdown(n):
while n > 0:
yield n
n -= 1


When you call this function:

gen = countdown(3)
print(next(gen)) # 3
print(next(gen)) # 2
print(next(gen)) # 1


Each time you call next(), the function resumes from where it left off, runs until it hits yield, returns a value, and pauses again.

---

β›” Why are the other options incorrect?

- Option 2 (class with __iter__ and __next__):
It works, but it’s more complex. Using yield is simpler and more Pythonic.

- Options 3 & 4 (for or while loops):
Loops are not generators themselves. They just iterate over iterables.

---

πŸ’‘ Pro Tip:
Generators are perfect when working with large or infinite datasets. They’re memory-efficient, fast, and clean to write.

---

πŸ“Œ #Python #Generator #yield #AdvancedPython #PythonTips #Coding


πŸ”By: https://t.iss.one/DataScienceQ
πŸ‘6❀2πŸ”₯2❀‍πŸ”₯1
Question 1 (Intermediate):
In Python, which of these is the correct way to create a virtual environment?

A) python create venv
B) python -m venv myenv
C) pip install virtualenv
D) conda make env

#Python #Development #VirtualEnv #Coding
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πŸ”₯ Trending Repository: tech-interview-handbook

πŸ“ Description: πŸ’― Curated coding interview preparation materials for busy software engineers

πŸ”— Repository URL: https://github.com/yangshun/tech-interview-handbook

🌐 Website: https://www.techinterviewhandbook.org

πŸ“– Readme: https://github.com/yangshun/tech-interview-handbook#readme

πŸ“Š Statistics:
🌟 Stars: 130K stars
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πŸ’» Programming Languages: TypeScript - JavaScript - Python

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==================================
🧠 By: https://t.iss.one/DataScienceM
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Here are links to the most important free Python courses with a brief description of their value.


1. Coursera: Python for Everybody
Link: https://www.coursera.org/specializations/python
Importance: A perfect starting point for absolute beginners. Covers Python fundamentals and basic data structures, leading to web scraping and database access.

2. freeCodeCamp: Scientific Computing with Python
Link: https://www.freecodecamp.org/learn/scientific-computing-with-python/
Importance: Project-based certification. You build applications like a budget app or a time calculator, reinforcing learning through practical, portfolio-worthy projects.

3. Harvard's CS50P: CS50's Introduction to Programming with Python
Link: https://cs50.harvard.edu/python/2022/
Importance: A rigorous university-level course. Teaches core concepts and problem-solving skills with exceptional depth and clarity, preparing you for complex programming challenges.

4. Real Python Tutorials
Link: https://realpython.com/
Importance: An extensive resource for all levels. Offers in-depth articles, tutorials, and code examples on nearly every Python topic, from basics to advanced specialized libraries.

5. W3Schools Python Tutorial
Link: https://www.w3schools.com/python/
Importance: Excellent for quick reference and interactive learning. Allows you to read a concept and test code directly in the browser, ideal for fast learning and checking syntax.

6. Google's Python Class
Link: https://developers.google.com/edu/python
Importance: A concise, fast-paced course for those with some programming experience. Includes lecture videos and well-designed exercises to quickly get up to speed.

#Python #LearnPython #PythonProgramming #Coding #FreeCourses #PythonForBeginners #Developer #Programming


By: t.iss.one/DataScienceQ πŸš€
❀2πŸ‘1
1. What is the primary data structure in pandas?
2. How do you create a DataFrame from a dictionary?
3. Which method is used to read a CSV file in pandas?
4. What does the head() function do in pandas?
5. How can you check the data types of columns in a DataFrame?
6. Which function drops rows with missing values in pandas?
7. What is the purpose of the merge() function in pandas?
8. How do you filter rows based on a condition in pandas?
9. What does the groupby() method do?
10. How can you sort a DataFrame by a specific column?
11. Which method is used to rename columns in pandas?
12. What is the difference between loc and iloc in pandas?
13. How do you handle duplicate rows in pandas?
14. What function converts a column to datetime format?
15. How do you apply a custom function to a DataFrame?
16. What is the use of the apply() method in pandas?
17. How can you concatenate two DataFrames?
18. What does the pivot_table() function do?
19. How do you calculate summary statistics in pandas?
20. Which method is used to export a DataFrame to a CSV file?

#️⃣ #pandas #dataanalysis #python #dataframe #coding #programming #datascience

By: t.iss.one/DataScienceQ πŸš€
❀1
1. What is the primary purpose of PHP?
2. How do you declare a variable in PHP?
3. Which symbol starts a PHP code block?
4. What is the difference between echo and print in PHP?
5. How do you create an array in PHP?
6. Which function is used to get the length of a string in PHP?
7. What is the use of the isset() function in PHP?
8. How do you handle form data in PHP?
9. What does the $_GET superglobal contain?
10. How can you include another PHP file in your script?
11. What is the purpose of the require_once statement?
12. How do you define a function in PHP?
13. What is the difference between == and === in PHP?
14. How do you connect to a MySQL database using PHP?
15. Which function executes a SQL query in PHP?
16. What is the use of the mysqli_fetch_assoc() function?
17. How do you start a session in PHP?
18. What is the purpose of the session_start() function?
19. How do you redirect a user to another page in PHP?
20. What is the use of the header() function in PHP?

#️⃣ #php #webdevelopment #coding #programming #backend #scripting #serverside #dev

By: t.iss.one/DataScienceQ πŸš€
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❔ Interview question

What is the output of the following code?
x = [1, 2, 3]
y = x
y.append(4)
print(x)

Answer:
[1, 2, 3, 4]

tags: #python #interview #coding #programming #datastructures #list #mutable #dev

By: t.iss.one/DataScienceQ πŸš€
❔ Interview question

What is the output of the following code?
def my_func():
return "hello", "world"

result = my_func()
print(type(result))

Answer:
<class 'tuple'>

tags: #python #interview #coding #programming #function #returnvalues #tuple #dev

By: t.iss.one/DataScienceQ πŸš€
❔ Interview question

What does the following code do?
import os
os.makedirs("folder/subfolder", exist_ok=True)

Answer:
Creates a directory named 'folder' with a subdirectory 'subfolder' if it doesn't already exist

tags: #python #os #filehandling #coding #programming #directory #makedirs #dev

By: t.iss.one/DataScienceQ πŸš€
❀1
KMeans Interview Questions

❓ What is the primary goal of KMeans clustering?

Answer:
To partition data into K clusters based on similarity, minimizing intra-cluster variance

❓ How does KMeans determine the initial cluster centers?

Answer:
By randomly selecting K data points as initial centroids

❓ What is the main limitation of KMeans regarding cluster shape?

Answer:
It assumes spherical and equally sized clusters, struggling with non-spherical shapes

❓ How do you choose the optimal number of clusters (K) in KMeans?

Answer:
Using methods like the Elbow Method or Silhouette Score

❓ What is the role of the inertia metric in KMeans?

Answer:
Measures the sum of squared distances from each point to its cluster center

❓ Can KMeans handle categorical data directly?

Answer:
No, it requires numerical data; categorical variables must be encoded

❓ How does KMeans handle outliers?

Answer:
Outliers can distort cluster centers and increase inertia

❓ What is the difference between KMeans and KMedoids?

Answer:
KMeans uses mean of points, while KMedoids uses actual data points as centers

❓ Why is feature scaling important for KMeans?

Answer:
To ensure all features contribute equally and prevent dominance by large-scale features

❓ How does KMeans work in high-dimensional spaces?

Answer:
It suffers from the curse of dimensionality, making distance measures less meaningful

❓ What is the time complexity of KMeans?

Answer:
O(n * k * t), where n is samples, k is clusters, and t is iterations

❓ What is the space complexity of KMeans?

Answer:
O(k * d), where k is clusters and d is features

❓ How do you evaluate the quality of KMeans clustering?

Answer:
Using metrics like silhouette score, within-cluster sum of squares, or Davies-Bouldin index

❓ Can KMeans be used for image segmentation?

Answer:
Yes, by treating pixel values as features and clustering them

❓ How does KMeans initialize centroids differently in KMeans++?

Answer:
Centroids are initialized to be far apart, improving convergence speed and quality

❓ What happens if the number of clusters (K) is too small?

Answer:
Clusters may be overly broad, merging distinct groups

❓ What happens if the number of clusters (K) is too large?

Answer:
Overfitting occurs, creating artificial clusters

❓ Does KMeans guarantee a global optimum?

Answer:
No, it converges to a local optimum depending on initialization

❓ How can you improve KMeans performance on large datasets?

Answer:
Using MiniBatchKMeans or sampling techniques

❓ What is the effect of random seed on KMeans results?

Answer:
Different seeds lead to different initial centroids, affecting final clusters

#️⃣ #kmeans #machine_learning #clustering #data_science #ai #python #coding #dev

By: t.iss.one/DataScienceQ πŸš€