Solving Real-World Data Science Interview Questions! (with Python Pandas)

In this video we solve a series of Data Science Interview questions on Stratascratch. We start with easy problems using Python Pandas and then progressively get more difficult. At the end of the video we do five non-coding interview questions that force you to think at a high level.

Mentioned Resources!

Here are the questions that we complete (in order)

~~ Coding ~~

~~ Non-Coding ~~

The skills that we work on in this video include:
- Python Pandas
- Groupby & Aggregate DataFrames
- Use regexes to analyze text
- Datetime objects in Pandas
- Filtering by Conditionals
- Applying a lambda function to a data frame

If you have any questions, let me know in the comments!

If you enjoyed this video, make sure to throw it a like & subscribe for all future content :)

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Video Timeline!
0:00 - Intro & Video Overview
0:46 - Check out this Video’s Sponsor, Brilliant!
3:10 - Coding #1 (Microsoft, Easy) - Finding Updated Records
10:36 - Coding #2 (Airbnb, Easy) - Number of Bathrooms and Bedrooms
16:38 - Coding #3 (Google, Medium) - Counting Instances in Text
28:23 - Coding #4 (Meta/Facebook, Medium) - Customer Revenue in March
36:51 - Coding #5 (Amazon, Hard) - Monthly Percentage Difference
56:38 - Coding #6 (Microsoft, Hard) - Premium vs Freemium
01:10:28 - Non-Coding #1 (Visa, Easy) - Credit Card Activity
01:13:33 - Non-Coding #2 (IBM, Easy) - Outliers Detection
01:16:46 - Non-Coding #3 (Google, Medium) - Probability of Having a Sister
01:27:19 - Non-Coding #4 (Uber, Medium) - Uber Black Rides
01:36:57 - Non-Coding #5 (Capital One, Hard) - Terabyte of Data
01:46:41 - Video Conclusion & Recap

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[KeithGalli]

Hope you all enjoyed this video :). I'm working on a bunch of new content right now so be on the lookout for another video or two in the next couple of weeks. If you have any questions about the topics covered in this or have a request for a future video, let me know here in the comments!!

[hardiktyagi]

At 37:48
I work for Amazon's RPA team, trying to make a career in data science. Last month I was appearing for an IJP and got the same question in SQL coding round.
Thanks for making this Keith. Keep them coming.

[yogeshuttekar]

Glad to see you back mate. I have really learned more from your videos than attending University.

[nicholasgrandizio]

Thank you for all the hard work you put into teaching Data Science. Your videos and others like you, provide more to the community such as myself trying to build a career in data than what University Programs provide. Your playing an important role in the future of Data Science by leading current students along the path to future industry leaders.

[deepaksaikumar]

Hi Keith,

You have been a great resource to learn Python and Data science-related skills.

Thank you!

[masked]

You're literally the best tutor I have seen, I myself am a Data Scientist but the amount of data science approaches I learn from you is incredible, I started from your channel and always wait for you to post new video, Hat's off. Love from Pakistan.

[danielefarotti]

I really like your approach in explaining things. I am currently transitioning from pure maths into data science, and I find these videos very helpful!

[BOGABOOfull]

Glad you're back bro ;) love this types of vids. Love from Portugal

[dinkinflicka]

Yay! Another real world problem solving video. Thanks Keith. Love your content as always.

[Lnd]

Here's a one liner chained version I've come up with for coding #6
df = ms_user_dimension.merge(ms_acc_dimension, on =
, on ='user_id').pivot_table(index = 'date', columns = 'paying_customer', values = 'downloads', aggfunc > yes')

[netanelmad]

Thanks for the video! Would love to see your approach to more non-coding questions specifically :)

[laurentreynaud]

Thank you so much for these data science courses!

[adeafni]

Thank you Keith, you're amazingg, keep it up!!!

[troy]

Thanks for the video. It is great to see your thinking process even though you are not an expert in pandas.

[niteshprajapat]

You are gem ❤️ the way you explain concepts are at next level 🔥🔥

[expat]

I really enjoy the real world feel of your videos. Probably now ChatGPT would be a lot faster than searching Stackoverflow or the Pandas docs for those things that one doesn't know by heart.

[ansekao]

Great video, please do more like that. Watching you for a long time

[iamTHIEN]

Hi Keith, Thank you so much for these videos, could you make more videos about power PI or Tableau, really really appreciate it .

[wiz]

Great work man!! you're always doing the best.🔥🔥🔥

[zanerios]

really love the style and format of vid, just subbed