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'}
)
}
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5 years, the cmdlet I had pasted in the original answer has undergone so many updates that it has become completely outdated.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.
The ConvertTo-Expression cmdlet can be download from PowerShell Gallery using the command:
Install-Script -Name ConvertTo-Expression
The full ReadMe (and source code) is available from the GitHub
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.)
Install-Script ConvertTo-Expression -Scope AllUsers which places the script into $env:ProgramFiles\WindowsPowerShell\Scripts (which might not exit if this is your first script). That adds C:\Program Files\WindowsPowerShell\Scripts (typical path) to your $env:path but only elevated. Back to standard ps and do $env:Path = "$env:Path$env:ProgramFiles\WindowsPowerShell\Scripts;" then just . ConvertTo-Expression.ps1 in any prompt or script you want to use it. Call function as ConvertTo-Expression ...Install-Script to do [Environment]::SetEnvironmentVariable('path',$env:path,'machine') to add the ...\WindowsPowerShell\Scripts dir to the path for the whole system, elevated and non elevated PS and everything else.
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
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
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.
[pscustomobject] @{name="foo";age=21}
[pscustomobject] @{name="foo";age=21}, but you cannot use that in data files loaded withImport-PowerShellDataFile, which only support hashtable literals)