JSON Array in PowerShell

Question

Am trying to generate the below JSON string in PowerShell:

[
    {
        "FirstName": "Test",
        "LastName": "Account2"
    }
]

The code I have at the moment in PowerShell is:

$Body = @{
    @{
        FirstName='Test'
        LastName='Account2'
     }
}

The error I get with this is: Missing '=' operator after key in hash literal.

score 23 · Accepted Answer · answered Oct 25 '16 at 03:19

23

The outer [] is a list in JSON and you're trying to use @{}, which is a hashtable in PowerShell. Use @() which is an array (list) in PowerShell:

$Body = @(
    @{
        FirstName='Test'
        LastName='Account2'
    }
)
ConvertTo-Json -InputObject $Body

(and I use -InputObject instead of piping, because PowerShell is obsessed with flattering lists, and drops the list otherwise).

answered Oct 25 '16 at 03:19

TessellatingHeckler

27,511
4
48
87

1

Thanks! That works a treat. I have also updated the script to use the InputObject as you mentioned. Thanks again! – Zac Oct 25 '16 at 04:23
1

This helped me with a similar issue as well, thanks! – mhouston100 Jan 31 '23 at 23:00
Good point about the -InputObject Vs Piping. Solved my issue. – Epirocks Feb 21 '23 at 11:45

score 1 · Answer 2 · answered Jan 10 '19 at 10:39

1

I had some problems adding new items to the Powershell list. I tried to add an item using the .add() function. This returned the error "Collection was of a fixed size."

Adding items to the list is just simple by using the += symbol.

$Body += @{FirstName='Test2'; LastName='Account3'}

That simple.

answered Jan 10 '19 at 10:39

daniel overdevest

33
4

1

Careful, += is supposed to be pretty expensive because it creates a new array with the new element appended to the end. Then replaces the old array with the new one. See https://stackoverflow.com/questions/14620290/array-add-vs – Tom Padilla Feb 27 '19 at 15:53

JSON Array in PowerShell

2 Answers2