I want to output a formated string to console. I have one string variable and one string array variable.
When I do this:
$arr = "aaa","bbb"
"test {0} + {1}" -f "first",$arr
The output is this:
test first + System.Object[]
But I need output to be:
test first + aaa,bbb
Or something similar...
Several options:
Join the array first, so you don't rely on the default ToString() implementation (which just prints the class name):
PS> 'test {0} + {1}' -f 'first',($arr -join ',')
test first + aaa,bbb
Use string interpolation:
PS> $first = 'first'
PS> "test $first + $arr"
test first + aaa bbb
You can change the delimiter used by setting $OFS, which by default is a space:
PS> $OFS = ','
PS> "test $first + $arr"
test first + aaa,bbb
You can get the same result (including the note about $OFS) with
PS> 'test {0} + {1}' -f 'first',(''+$arr)
test first + aaa bbb
This forces the array to be converted into a single string first, too.
-f is just a straightforward convenience for String.Format(), it uses the same semantics as .NET in that regard. String interpolation is a tricky subject, as it converts objects to string using the invariant culture (apparently); it will also join arrays using $OFS. Generally I don't feel confident right now to accurately summarise the exact differences. Something fun: $a = (date),(date),(date); Write-Host $a; Write-Host "$a"