Mirror of forum.nim-lang.org

9292 :: Help with sorting a sequence of objects

• wreedb (orginal) [2022-07-08T09:28:34+02:00] view original

  I'm writing a package manager, and it has a search function that returns a list of packages.

  • these packages all have a field called 'NumVotes' which is an int, which has to do with their popularity.
  • I am trying to sort these packages in a sequence with lower indexes yielding higher 'NumVotes' values

  How would I go about this? I tried using the std/algorithm sort and sorted proc, but they yielded me some quite unhelpful compilation errors.

  here is an example of the objects:

  
  type
    Package* = object
      Name*         : string
      Description*  : string
      Version*      : string
      URLPath*      : string
      LastModified* : int
      NumVotes*     : int
  Run

  and here is an example of a sequence of two of the objects:

  @[(Name: "fastfetch-git", Description: "Like neofetch, but much faster because written in c", Version: "1.5.1.r0.gdbe24c7-1", URLPath: "/cgit/aur.git/snapshot/fastfetch-git.tar.gz", LastModified: 1654681264, NumVotes: 11), (Name: "fastfetch", Description: "Like Neofetch, but much faster because written in C", Version: "1.5.6-1", URLPath: "/cgit/aur.git/snapshot/fastfetch.tar.gz", LastModified: 1656861723, NumVotes: 7)]

---

• Yardanico (orginal) [2022-07-08T09:46:57+02:00] view original

  import std/algorithm
  
  type
    Package* = object
      Name*         : string
      Description*  : string
      Version*      : string
      URLPath*      : string
      LastModified* : int
      NumVotes*     : int
  
  # fastfetch has less votes
  var pkgs = @[
    Package(Name: "fastfetch", Description: "Like Neofetch, but much faster because written in C", Version: "1.5.6-1", URLPath: "/cgit/aur.git/snapshot/fastfetch.tar.gz", LastModified: 1656861723, NumVotes: 7),
    Package(Name: "fastfetch-git", Description: "Like neofetch, but much faster because written in c", Version: "1.5.1.r0.gdbe24c7-1", URLPath: "/cgit/aur.git/snapshot/fastfetch-git.tar.gz", LastModified: 1654681264, NumVotes: 11)
  ]
  
  proc cmpPkgs(a, b: Package): int =
    cmp(a.NumVotes, b.NumVotes)
  
  pkgs.sort(cmpPkgs, Descending)
  echo pkgs[0].Name
  Run

  But please don't use PascalCase field names as the fields in the object :)

---

• wreedb (orginal) [2022-07-08T09:58:49+02:00] view original

  Oh my goodness, thank you so much for the help, it worked like a charm!

  PS: I totally forgot about the field names, they were only like that because I was originally filling them directly from JSON, was dying to change them, thanks for the reminder!

---