Hashtables from ConvertFrom-json have different type from powershells built-in hashtables, how do I make them the same?

Question

I have a json file (test.json) that looks something like this:

{
    \"root\":
    {
        \"key\":\"value\"
    }
}

I\'m loading it into

Answer 1

The ConvertFrom-Json cmdlet gives you a custom object so you have to access them using dot notation rather than as a subscript. Usually you would know what fields you expect in the JSON so this is actually more useful in general than getting a hash table. Rather than fighting the system by converting back to a hash table, I suggest you work with it.

You can use select with wildcard property names to get at the properties:

PS D:\> $data = @"
{
    "root":
    {
        "key":"value", "key2":"value2", "another":42
    }
}
"@ | ConvertFrom-Json

PS D:\> $data.root | select * | ft -AutoSize

key   key2   another
---   ----   -------
value value2      42



PS D:\> $data.root | select k* | ft -AutoSize

key   key2  
---   ----  
value value2

and Get-Member if you want to extract a list of property names that you can iterate over:

PS D:\> ($data.root | Get-Member -MemberType NoteProperty).Name
another
key
key2

Putting that into a loop gives code like this:

PS D:\> foreach ($k in ($data.root | Get-Member k* -MemberType NoteProperty).Name) {
    Write-Output "$k = $($data.root.$k)"
    }
key = value
key2 = value2