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5294 :: Sequence of objects which contain a sequence

• MaineTim (orginal) [2019-10-07T03:06:47+02:00] view original

  Hi - new to Nim and working through a program to massage a large file of data represented by the type

   type TSegment* = object
    ignore: bool
    start: DateTime
    finish: DateTime
    duration: Duration
    sequence: int
    code: char
    data: string
    token: string
    date: string
    deductions: seq[int]
  Run

  I then create a sequence of that type

   var segment: TSegment
   var segments = newSeqofCap[TSegment](1)
  Run

  and add a bunch of segments to it.

   segments.add(segment)
  Run

  So now I have a mutable sequence of TSegments, which can be accessed as segments[x]. How do I initialize and add to segment[x].deductions? I've tried:

  • directly initializing segment[x].deductions as

     newSeqofCap[int](1)
    Run

  • creating a separate seq[int] and assigning it to segment[x].deductions
  • creating a separate seq[int] and adding it to segment[x].deductions

  but no luck.

  Thanks!

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• GordonBGood (orginal) [2019-10-07T09:11:27+02:00] view original

  @MaineTim: Yup, new to Nim...

  In the following, I've shortened your code just to show the essentials:

  type
    TSeg = object
      sub: seq[int]
  
  var seg = TSeg(sub: @[])
  var segments = newSeq[TSeg]()
  
  for i in 0 .. 2: segments.add seg
  
  segments.echo
  
  segments[2].sub.add(7)
  segments.add(TSeg(sub: @[42]))
  
  segments.echo
  Run

  No need to create the seq's using capacities (unless you are optimizing), creating all the elements from your uninitialized model of segment doesn't actually create any sub sequences as the default values are all zeros, including the deductions sub field, so you can't assign or add to it until it has been created with some sort of a new. In my example code, I initialized the model seg including initializing its seq contents with seq literal initializer as in @[] but you could use any sort of newSeq or newSeqOfCap, then either assign to the existing elements or add to the elements as you wish as I have done here.

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• MaineTim (orginal) [2019-10-07T11:55:21+02:00] view original

  Thanks, @GordonBGood!

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