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8936 :: Correct way have for-loop iteration up to number of only initialized array elements

• mardiyah (orginal) [2022-02-21T08:33:01+01:00] view original

  How to limit for loop iteration up to number of only initialized or filled array elements

  
  var
    d = newSeq[ array[2,string]](70)
  
  d[0] = ["foo", "bar"]
  d[1] = ["moo", "dar"]
  
  for u in d :           # ... so on
                               # will loop 70 times instead of twice
  Run

  explain the correct Nim on it

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• dwin (orginal) [2022-02-21T08:56:04+01:00] view original

  Use newSeqOfCap instead of newSeq

  var d = newSeqOfCap[array[2, string]](70)
  
  d.add ["foo", "bar"]
  d,add  ["moo", "dar"]
  
  for u in d:
    ...
  Run

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• mardiyah (orginal) [2022-02-21T10:08:12+01:00] view original

  worried get reallocation process, is the same as nr=ew Seq it'll avoid reallocation cost ?

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• ElegantBeef (orginal) [2022-02-21T10:48:03+01:00] view original

  newSeqOfCap[int](70) is just like newSeq[int](70) the only difference is the first only sets the capacity and it doesnt add any elements so it's an "empty" allocated sequence. So it avoids more allocation the same but len is 0

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