Listing all environment variables that starts with a string

[cronhan]

Good day, new-ish on-and-off user here.
I did a cursory search for this (here and on Google/DDG) but I could not find an answer, and my knowledge of Nu is not yet what it should be :) So here is my question:
In CMD, I can do the following:

> set a
ALLUSERSPROFILE=C:\ProgramData
APPDATA=C:\Users\user\AppData\Roaming

Same thing in PowerShell:

> Get-ChildItem env:a*
Name                           Value
----                           -----
APPDATA                        C:\Users\user\AppData\Roaming
ALLUSERSPROFILE                C:\ProgramData

How can I accomplish the same in nu? Things I have tried that do not work:

~> $env.a*
Error: nu::shell::column_not_found

~> $env | select a*
Error: nu::shell::column_not_found

~> $env | str starts-with 'a'
Error: nu::shell::only_supports_this_input_type

~> $env | any {|| $in.startswith "a"}
Error: nu::parser::parse_mismatch

[Jan9103]

$env | transpose key value | where ($it.key | str starts-with 'a')

since $env is a record and not a table we first have to transpose it to one in order to make it properly iterable. -> transpose key value

and now we can use where, which filters a list/table (and it allows the use of the spicial variable $it)

[cronhan]

Thank you so much for the detailed explanation! My next task is to make my first function using this knowledge :)