This is something that keeps throwing me, I figured out a work around a few weeks back but I forgot:

$l=[System.Collections.Generic.List[string[]]]::new()
$l.Add("one", "two", "three")
$l.ToString()                                                  #returns ---> System.String[]
"$l"                                                           #returns ---> System.String[]           
 [string]$l                                                  #returns ---> System.String[]       
 $l -join "`n"                                              #returns ---> System.String[]       

I am expecting something like the following or something else as dictated by the $ofs variable:

one
two
three

Am on pwsh 7.4

This is something that keeps throwing me, I figured out a work around a few weeks back but I forgot:

$l=[System.Collections.Generic.List[string[]]]::new()
$l.Add("one", "two", "three")
$l.ToString()                                                  #returns ---> System.String[]
"$l"                                                           #returns ---> System.String[]           
 [string]$l                                                  #returns ---> System.String[]       
 $l -join "`n"                                              #returns ---> System.String[]       

I am expecting something like the following or something else as dictated by the $ofs variable:

one
two
three

Am on pwsh 7.4

• list
• powershell

• 1 @Olaf, correct, the .add() has a mistake that I often fall for, I over looked while writting this quesiont. I meant $l.Add(("one", "two", "three")). mklement0 linked to the $ofs section of the docs, below. – Ralf_Reddings Commented yesterday

2 Answers 2

Leaving aside that the $l.Add("one", "two", "three") call cannot work, I assume that your intent is to create a list whose elements are strings ([string]) rather than arrays of strings ([string[]]).

Therefore, change:
$l=[System.Collections.Generic.List[string[]]]::new()
to:
$l=[System.Collections.Generic.List[string]::new()

To put it all together:

# Create a list whose elements are strings.
$l = [System.Collections.Generic.List[string]]::new()
# Add 3 elements; note the use of .AddRange() rather than .Add()
$l.AddRange([string[]] ("one", "two", "three"))

$l.ToString() # -> 'System.Collections.Generic.List`1[System.String]'

"$l"           # -> 'one two three'
[string] $l    # ditto
$l -join "`n"  # -> "one`ntwo`nthree"

Note that "$l" and [string] $l do respect the value of the $OFS preference variable, if defined; in the latter's absence, a single space is used.

The following code, gets the result, but I'm in 7.5:

$l=[System.Collections.Generic.List[string[]]]::new()
$l.Add("one")
$l.Add("two")
$l.Add("three")
$l