• kdb+

  Accessing the last element of List of List

  Posted by ekallivrousis on December 8, 2021 at 12:00 am

  x:(`Col1;12;.z.Z) y:(x;x;x) 
  //add gtime of last element to end of x 
  x,@[gtime;last x;0Np] 
  //How do i do this for y?

  So i think i did x correctly unless theres a better way. But how would i handle y? I want to append to end of each list in y.

  ekallivrousis replied 8 months, 1 week ago 2 Members · 3 Replies
• 3 Replies

• 

  soheir

  Member

  December 8, 2021 at 12:00 am

  This might be what you’re looking for then

  q) x1:(`Col1;12;.z.Z) 
  q) x2:(`Col1;12;`ERROR) 
  q) show y:(x1;x1;x1;x2) 
  `Col1 12 2021.12.08T17:46:26.162 
  `Col1 12 2021.12.08T17:46:26.162 
  `Col1 12 2021.12.08T17:46:26.162 
  `Col1 12 `ERROR 
  q) {x,@[gtime;last x;0Np]}each y 
  `Col1 12 2021.12.08T17:46:26.162 2021.12.08T17:46:26.162 
  `Col1 12 2021.12.08T17:46:26.162 2021.12.08T17:46:26.162 
  `Col1 12 2021.12.08T17:46:26.162 2021.12.08T17:46:26.162 
  `Col1 12 `ERROR 0Np

   

• 

  soheir

  Member

  December 8, 2021 at 12:00 am

  Hey @ekallivrousis – is this what you’re trying to do?

  q)x:(`Col1;12;.z.Z)
  q)y:(x;x;x)
  
  `Col1 12 2021.12.08T17:33:36.400
  `Col1 12 2021.12.08T17:33:36.400
  `Col1 12 2021.12.08T17:33:36.400
  q)y,'gtime .z.P
  
  `Col1 12 2021.12.08T17:33:36.400 2021.12.08D17:33:47.617397000
  `Col1 12 2021.12.08T17:33:36.400 2021.12.08D17:33:47.617397000
  `Col1 12 2021.12.08T17:33:36.400 2021.12.08D17:33:47.617397000

  Or are you looking to use the last item of each list of y (list of lists) as an input to gtime ?

• 

  ekallivrousis

  Member

  December 8, 2021 at 12:00 am

  Close, i want it to be in protected eval @[], also i dont want to convert current .z.P i want to convert the last col of each list in y. I bold the column below that i want to use

  `Col1 12 2021.12.08T17:33:36.400
  `Col1 12 2021.12.08T17:33:36.400
  `Col1 12 2021.12.08T17:33:36.400

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