• KX Academy

  partitioned exercise question

  Posted by lestat-jin on June 27, 2024 at 10:13 pm

  from the level 3 partitioned exercise:<b style=”background-color: var(–bb-content-background-color); font-family: inherit; font-size: inherit; color: var(–bb-body-text-color);”> allPaths

  given solution: allPaths:{[dir]sv'dir,'k where(k:key dir)like"[0-9]*"}</i></b></p><p>my functional solution: <b><i>allPaths: {[dir] sv[; ‘dir, ‘k where (k: key dir) like “[0-9]*”]}

  which returned stype evaluation error, due to the ‘ in front of dir.

  It makes sense to remove the ‘ before dir and keep the one in front of k, given dir should only has one element and k can be a list ( and so the “each”). just wondering why is it in the solution that there is the ‘ between sv and dir, and that it works?

  Thanks,

  edu.kx.com

  JupyterHub - KX

  JupyterHub - KX

  lestat-jin replied 4 months, 3 weeks ago 2 Members · 7 Replies
• 7 Replies

• 

  lestat-jin

  Member

  June 27, 2024 at 10:15 pm

  apologies for the formatting issue, no idea how to fix it…

• 

  megan_mcp

  Administrator

  June 28, 2024 at 12:28 pm

  Hi @lestat-jin

  Apologies for the formatting issue on our side, we are working to fix this for future discussions.

  Would you be able to send a screenshot of the code so we can help better assist you?

  Thanks,

  Megan

  • 

    lestat-jin

    Member

    June 28, 2024 at 2:52 pm

    Sure, thanks.

    

    SmartSelect_20240628_154856_Samsung-Internet.jpg 293 KB Image File - Click to view

    Options

    • Copy Download Link
    • 

      megan_mcp

      Administrator

      July 1, 2024 at 9:17 am

      Hi @lestat-jin

      ` sv’… is the dyadic form of each, x f’y: https://code.kx.com/q/ref/maps/#each
      When ‘ is prefix — not in an adverb position — that’s signal/throw: https://code.kx.com/q/ref/signal/

      If you have any questions about this, feel free to reach out!

      Thanks,

      Megan

      code.kx.com

      Map iterators | Reference | kdb+ and q documentation - kdb+ and q documentation

      Maps iterators derive uniform functions that apply their values once to each item of a dictionary, a list, or conforming lists.

      • 

        lestat-jin

        Member

        July 2, 2024 at 5:03 pm

        Thanks, so in the second version (functional form, ‘ in front of one func argument), this is read as signal? in general each should not be put in a function form?

        • 

          megan_mcp

          Administrator

          July 3, 2024 at 2:19 pm

          Hi @lestat-jin

          If we take a look at the format for the functional form of each (screenshot below) you can see the quote is used outside the square brackets.

          So if I were to edit your answer it would look like:

          allPaths:{[dir] sv'[`;dir, 'k where(k:key dir) like "[0-9]*"]}
          

          I have removed the quote infront of dir and included it between sv and the square brackets as indicated in the documentation as this represents using each in functional form.

          Let me know if this answers your question !

          Thanks,

          Megan

          
          • 

            lestat-jin

            Member

            July 5, 2024 at 11:33 am

            thanks, that is very helpful!

Log In to Reply