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

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  • Опубликовано: 13 янв 2025

Комментарии • 88

  • @KeithGalli
    @KeithGalli  2 года назад +10

    Thank you Brilliant for sponsoring this video! Check out brilliant.org/KeithGalli/ to get started learning STEM for free, and the first 200 people will get 20% off their annual premium subscription.
    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!!

    • @edwardj.warden5072
      @edwardj.warden5072 2 года назад +1

      Hi @KeithGalli.
      I’ve got two questions to ask you. I have watched lots of your videos that I like, and learned a lot.
      My question is do you think that the certificate that Datacamp provides for data science is worth to earn, and would it help me to find a data science job?
      And, what best place, you recommend, in online to get certificate for data science that would help me to find a data science job?
      Thank you.

  • @hardiktyagi1955
    @hardiktyagi1955 2 года назад +37

    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.

    • @KeithGalli
      @KeithGalli  2 года назад +2

      Dang that's too funny. My hope is that this video will help people in similar situations to yours moving forward. Thanks for watching!

    • @shivamburnwal7765
      @shivamburnwal7765 2 года назад

      Hey Hardik, can you tell me why exactly you are trying to make a career in Data Science? Is it because RPA doesn't have a good future in the industry or it is because you personally prefer the Data Science field. I am asking this question as I am also starting as a member of EXL's RPA team.

  • @Frdy12345
    @Frdy12345 2 года назад +2

    Here's a one liner chained version I've come up with for coding #6
    df = ms_user_dimension.merge(ms_acc_dimension, on = 'acc_id').merge(ms_download_facts
    ,on ='user_id').pivot_table(index = 'date',columns = 'paying_customer',values = 'downloads',aggfunc ='sum').reset_index().query('no > yes')

  • @danielefarotti1061
    @danielefarotti1061 Год назад +4

    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!

  • @masked00000
    @masked00000 2 года назад +4

    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.

  • @arashomranpour5468
    @arashomranpour5468 2 года назад +6

    good having you back

  • @yogeshuttekar8542
    @yogeshuttekar8542 2 года назад +5

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

  • @expat2010
    @expat2010 Год назад +1

    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.

  • @dinkinflicka157
    @dinkinflicka157 2 года назад +2

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

    • @KeithGalli
      @KeithGalli  2 года назад +2

      Glad to hear it, I appreciate your support!! :)

  • @jovanjanjic9029
    @jovanjanjic9029 Год назад

    In question #3 Counting Instances in Text you should add filters=re.I to account for capital letters: len(re.findall(r'\bbull\b', text, flags=re.I)))

  • @bobbyg603
    @bobbyg603 2 года назад +1

    Glad you're back bro!

  • @deepaksaikumar5178
    @deepaksaikumar5178 2 года назад +2

    Hi Keith,
    You have been a great resource to learn Python and Data science-related skills.
    Thank you!

  • @nicholasgrandizio7596
    @nicholasgrandizio7596 2 года назад +3

    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.

  • @phoenixcollege6608
    @phoenixcollege6608 2 года назад

    makes it easy to understand
    watching your vid on a friday night and these are the best years of my young life

  • @MiguelNFer
    @MiguelNFer 2 года назад

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

  • @mekuzeeyo
    @mekuzeeyo 2 года назад +1

    Thank you for coming back🤗

  • @zanerios2776
    @zanerios2776 2 года назад

    really love the style and format of vid, just subbed

    • @KeithGalli
      @KeithGalli  2 года назад

      Glad you liked it man! Thanks for the sub

  • @troy671
    @troy671 2 года назад

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

  • @laurentreynaud4404
    @laurentreynaud4404 2 года назад +1

    Thank you so much for these data science courses!

  • @phsopher
    @phsopher 2 года назад +4

    For the fifth problem, pandas has an in-built percentage difference method (pct_change). The solution could be as follows for example:
    sf_transactions['year_and_month'] = sf_transactions.created_at.dt.strftime("%Y-%m")
    monthly_revenue = sf_transactions.groupby(["year_and_month"]).sum().reset_index()
    monthly_revenue['pct_change'] =(monthly_revenue.value.pct_change()*100).round(2)
    monthly_revenue[['year_and_month','pct_change']]

    • @KeithGalli
      @KeithGalli  2 года назад +3

      Oh cool, I didn't know that! Thanks for sharing :). Nice solution 🤠.

  • @iamTHIEN013
    @iamTHIEN013 Год назад

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

  • @netanelmad
    @netanelmad 2 года назад

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

  • @niteshprajapat7918
    @niteshprajapat7918 2 года назад +1

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

  • @kennethstephani692
    @kennethstephani692 Год назад

    Great video, Keith!

  • @anonviewerciv
    @anonviewerciv 2 года назад

    That first one and others are SQL problems converted to pandas. I suppose that's a decent way to get basic pd questions. (28:48)
    17:20 I know it's more a reference to the stock market terms, but I can't stop thinking of Fallout: New Vegas.
    1:11:00 If you have the locations that's just a simple matter of putting it on a map and seeing where it clusters the most.
    1:28:00 Context, context, context. Was that the only reduction?

    • @konstantinpluzhnikov4862
      @konstantinpluzhnikov4862 2 года назад +1

      These stratascratch tasks could be solved in sql. The site provides this option.

  • @a.5214
    @a.5214 2 года назад +2

    amazing! we want more of this stuff 👌

    • @KeithGalli
      @KeithGalli  2 года назад +2

      Appreciate it! More coming soon :)

  • @omer55kurt
    @omer55kurt 2 года назад +2

    Yeeeeeeeeyyy!!!! i love your enthusiastic cry of success :D 26:31

  • @ansekao4516
    @ansekao4516 2 года назад

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

  • @edwardj.warden5072
    @edwardj.warden5072 2 года назад

    Very helpful. Thank you Keith.

  • @wahaha108
    @wahaha108 2 года назад

    long time no see keith, welcome back 😀😀

  • @adeafni9544
    @adeafni9544 2 года назад

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

  • @kumaripritika2799
    @kumaripritika2799 2 года назад +1

    Really helpful video!

  • @n_12346
    @n_12346 Год назад

    Brilliant video! very helpfil

  • @wiz8058
    @wiz8058 2 года назад

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

    • @KeithGalli
      @KeithGalli  2 года назад

      Thank you for the support as always!!

  • @DendrocnideMoroides
    @DendrocnideMoroides 2 года назад

    yes please make more videos like this

  • @AIdevel
    @AIdevel 2 года назад

    The problem lays in your use of round function you supposed to wrap the equation with round and then select the decimals 2

  • @udayabhaskar1495
    @udayabhaskar1495 2 года назад

    Thank you for this video!👍

  • @pratikpawar336
    @pratikpawar336 2 года назад

    great video, please make more video like this

  • @prof_albert
    @prof_albert 2 года назад

    That was great. Bravo and all of your videos are awesome 🌺👌💞🤩💪

  • @АндрейТоцкий-л4и
    @АндрейТоцкий-л4и 9 месяцев назад

    It is very great. Thank You!

  • @iamfavoured9142
    @iamfavoured9142 2 года назад

    Welcome back Keith 💃🏻💃🏻

  • @fantasyxpress7966
    @fantasyxpress7966 Год назад

    Is dsa important for data scientists too keith

  • @user-zm6kj7oi3d
    @user-zm6kj7oi3d 2 года назад +1

    you are helping a high schooler out by being back

    • @KeithGalli
      @KeithGalli  2 года назад +2

      More videos coming soon :)

  • @9eartheyes
    @9eartheyes 2 года назад

    great video! thank you!

  • @ranjithraghunathan1267
    @ranjithraghunathan1267 2 года назад

    Thanks Keith

  • @mohanadashour4835
    @mohanadashour4835 3 месяца назад

    I think that for the probability of getting a sister given that they have 2 children is 0.75
    Sample space
    Sister,brother
    Brother,sister
    Sister,sister
    Brother,brother
    3/4
    And for 3 children you need to account for the chance that the three children are girls so it will be 7/8

  • @CultureofSpeech
    @CultureofSpeech 7 месяцев назад

    Bravo 👏 Lit 🌠 Impressive 👌 ❤ Gratitude 🥳 for your satisfactory Work 💪🚀💯💪

  • @MikeResurrected
    @MikeResurrected Год назад

    Could you actually google for help during a DS coding interview nowadays?

  • @fcoatis
    @fcoatis 2 года назад

    Great video Keith. I just got curious how you comment a block of code?

    • @kinghezzy
      @kinghezzy Год назад

      Highlight and ctrl+/

  • @RahmanIITDelhi
    @RahmanIITDelhi 2 года назад

    Hey ,Keith ..Can we access library during the solving at real time exam?

  • @SerDunk-224
    @SerDunk-224 Месяц назад

    Hey Keith, dunno if this changed from 2 years ago when you posted this video, but currently the 'Check Solution' button is only available for Premium Users :/
    Still, seeing how you go about solving the problems is great to get in the right mindset!

  • @vanshmalik1446
    @vanshmalik1446 2 года назад

    Hey!
    Does anyone knows more of the data analysis pay after placement programs accepting applications all over the globe?

  • @ranjithraghunathan1267
    @ranjithraghunathan1267 2 года назад

    how can i download or copy the raw dataset for each part ?

  • @mehdismaeili3743
    @mehdismaeili3743 2 года назад

    excellent, thanks.

  • @AIdevel
    @AIdevel 2 года назад

    Replace yes with 1 and no with zero and sum them

  • @konstantinpluzhnikov4862
    @konstantinpluzhnikov4862 2 года назад +2

    LifeHack: if you are short of money, but want to use a service, use vpn of relatively poor country. Result will be interesting.

  • @finnnelson5472
    @finnnelson5472 2 года назад

    TY :)

  • @manphu2515
    @manphu2515 2 года назад

    Thanks so much for the video, learn a lot from you. And you are super cute 😍

  • @jovanjanjic9029
    @jovanjanjic9029 Год назад +4

    Your solution for the Probability of Having a Sister question is not correct. We know for sure that the random girl must be from the [1, 2, 3, 4] part of the dataset, which amounts to 0.7. We should divide the probabilities for 1, 2, 3, 4 with 0.7, to get the probabilities that the girl is from each of these families. She theoretically can't be from families with 0 and 5 children. Essentially, you are counting in the possibilities of she being in families 0 and 5, even tough it's impossible. (In practical terms, you are needlessly being blind about the info you already have.) So the correct solution is: 0.25/0.7 x 0 + 0.2/0.7 x 0.5 + 0.15/0.7 x 0.75 + 0.1/0.7 x 0.875 = 0.42857, which is 0.43 when we round it up.

  • @balakumar.n4891
    @balakumar.n4891 2 года назад

    super

  • @Manishsingh-u1r9q
    @Manishsingh-u1r9q Месяц назад

    @KeithGalli I don't know why you look like Elon Musk must to me 🤣🤣

  • @meujie8835
    @meujie8835 2 года назад

    Hi, I'm Jiemeu and I love your channel. I hope to discuss business cooperation with you.....

  • @YunusFidan_
    @YunusFidan_ 2 года назад

    Noice!

  • @YaIdcReportMe
    @YaIdcReportMe 7 месяцев назад

    Probably not a good use of your time to watch this guy struggle with coding questions for over an hour

  • @doulaishamrashikhasan8425
    @doulaishamrashikhasan8425 2 года назад

    you disappeared again 😢

    • @KeithGalli
      @KeithGalli  2 года назад +3

      My apologies! I have a video that I'm finalizing the editing for. It should be out in the next 3-4 days and then I'm going to try to be more consistent!!

  • @ratkillerthe
    @ratkillerthe Год назад

    I solved the Bathrooms/Bedrooms problem with:
    cols_of_interest = airbnb_search_details[['city', 'property_type', 'bathrooms', 'bedrooms']]
    property_results = cols_of_interest.groupby(['city','property_type']).agg(
    avg_bathrooms = ('bathrooms', 'mean'),
    avg_bedrooms = ('bedrooms', 'mean')).reset_index()

  • @thebunnda5450
    @thebunnda5450 5 месяцев назад

    Simple Solution for #5
    (sf_transactions
    .assign(year_month = lambda df_: df_.created_at.dt.strftime('%Y-%m'))
    .groupby('year_month', as_index=False)
    .agg(revenue = ('value', 'sum'))
    .assign(revenue_diff_pct = lambda df_: df_.revenue.sub(df_.revenue.shift(1)).div(df_.revenue.shift(1)).mul(100))
    .loc[:, ['year_month', 'revenue_diff_pct']]
    )