PowerShell - Get only a string value

Question

Hi how do I get only the value test-staging-100 in the following dictionary

{ 
   "clusters": [
       "test-staging-100", 
       "test-local-1", 
       "test-dev-50" 
     ] 
}

when I ran this command

$cluster = aws list-clusters | Select-String "test-staging"

I keep getting "test-staging-100", . I don't want the quotation and comma but only test-staging-100

mklement0 · Accepted Answer · 2022-08-18 16:01:09Z

It looks like what the aws CLI returns is JSON text, so it's preferable to parse it into an object graph with ConvertFrom-Json and act on that:

[string] $cluster = 
  @((aws list-clusters | ConvertFrom-Json).clusters) -match '^test-staging'

Note:

The @(...) ensures that -match also works as intended - as a filter returning the matching element(s) - in case only one cluster happens to be returned.
When -match acts as a filter, it invariably returns an array, even if only one element of the LHS array matches; type constraint [string] converts such a one-element array to a single string.
If there's a chance that multiple elements match, more work is needed; to categorically use only the first, enclose the RHS of the assignment in (...)[0]

If you really wanted to use Select-String to search the raw string output (which is ill-advised), you'd have to do something like:

$cluster = (aws list-clusters | Select-String 'test-staging[^"]+').Matches.Value

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