A quick tour of building `argsort` with Nushell... enjoy!

building-argsort-with-nushell.md

You can define commands (like functions) like this (in the shell if you want for easy trial and error):

# Returns indices that would sort the input list
def argsort [--reverse (-r)]: list<number> -> list<int> {
    enumerate | sort-by item --reverse=$reverse | get index
}

Then you get nice help like this "for free":

> help argsort
Returns indices that would sort the input list

Usage:
  > argsort {flags}

Flags:
  -h, --help: Display the help message for this command
  -r, --reverse

Input/output types:
  ╭───┬──────────────┬───────────╮
  │ # │    input     │  output   │
  ├───┼──────────────┼───────────┤
  │ 0 │ list<number> │ list<int> │
  ╰───┴──────────────┴───────────╯

This shows it in action... Nushell leans heavily on pipelines:

[2.2 4.4 5.5 1.1 3.3] | argsort

╭───┬───╮
│ 0 │ 3 │
│ 1 │ 0 │
│ 2 │ 4 │
│ 3 │ 1 │
│ 4 │ 2 │
╰───┴───╯

[2.2 4.4 5.5 1.1 3.3] | argsort -r

╭───┬───╮
│ 0 │ 2 │
│ 1 │ 1 │
│ 2 │ 4 │
│ 3 │ 0 │
│ 4 │ 3 │
╰───┴───╯

I used floats just because you can. Other shells like Bash and Zsh do floats either via workarounds or with extra syntax, but neither treat floats as first-class values.)