Save hash table in PowerShell object notation (PSON) - powershell

Question

The question Loading a PowerShell hashtable from a file? documents how to load a file that contains a hashtable in PSON format into a variable, but how does one save a hashtable to a file in PSON format?
Hashtable:
#{
"name" = "report 0"
"parameters" = #(
#{"name" = "parameter 0"; "default" = 1; "values"=1,2,3,4},
#{"name" = "parameter 1"; "default" = 'A'; "values" = 'A','B','C'}
)
}

Answer 1

After 5 years, the cmdlet I had pasted in the original answer has undergone so many updates that it has become completely outdated. Therefore I have replaced the code and the ReadMe with a link to the latest version.
ConvertTo-Expression
The ConvertTo-Expression cmdlet can be download from PowerShell Gallery using the command:
Install-Script -Name ConvertTo-Expression
ReadMe
The full ReadMe (and source code) is available from the GitHub
Answer
Below are some possible options to serialize the specific example (assigned to $Craig) in the question:
ConvertTo-Expression $Craig
#{
parameters =
#{
name = 'parameter 0'
default = 1
values =
1,
2,
3,
4
},
#{
name = 'parameter 1'
default = 'A'
values =
'A',
'B',
'C'
}
name = 'report 0'
}
To limit the tree view expansion:
(Expand -0 will output a single line and Expand -1 will remove also the unnecessary spaces)
ConvertTo-Expression $Craig -expand 3
#{
parameters =
#{name = 'parameter 0'; default = 1; values = 1, 2, 3, 4},
#{name = 'parameter 1'; default = 'A'; values = 'A', 'B', 'C'}
name = 'report 0'
}
Preserving the explicit types (strong typed):
ConvertTo-Expression $Craig -expand 3 -Strong
[hashtable]#{
parameters = [array](
[hashtable]#{name = [string]'parameter 0'; default = [int]1; values = [array]([int]1, [int]2, [int]3, [int]4)},
[hashtable]#{name = [string]'parameter 1'; default = [string]'A'; values = [array]([string]'A', [string]'B', [string]'C')}
)
name = [string]'report 0'
}
(Note: As per PowerShell design, HashTables are not in order, but if required you might use the [Ordered] type instead.)

Answer 2

Try the *-CliXml cmdlets. To save the object:
#{
"name" = "report 0"
"parameters" = #(
#{"name" = "parameter 0"; "default" = 1; "values"=1,2,3,4},
#{"name" = "parameter 1"; "default" = 'A'; "values" = 'A','B','C'}
)
} | Export-Clixml -Path c:\hash.xml
To read it back:
Import-Clixml c:\hash.xml

Answer 3

One way would be to put the hashtable definition in a scriptblock:
$hashtable = {
#{
"name" = "report 0"
"parameters" = #(
#{"name" = "parameter 0"; "default" = 1; "values"=1,2,3,4},
#{"name" = "parameter 1"; "default" = 'A'; "values" = 'A','B','C'}
)
}
}
$hashtable.tostring()
#{
"name" = "report 0"
"parameters" = #(
#{"name" = "parameter 0"; "default" = 1; "values"=1,2,3,4},
#{"name" = "parameter 1"; "default" = 'A'; "values" = 'A','B','C'}
)
}
Within the script, you'd need to invoke the script block to instantiate the hashtable:
$hash = .$hashtable

Answer 4

How to use a shorthand "object notation" to generate an object in PowerShell:
$object = New-Object -TypeName PSObject -Property #{name="foo";age=21}
DISCLAIMER: I know this does not answer OP's question directly but it might help folks like me searching for a very similar issue and landing here.