Hash Table to CSV

I’m was sitting here, and I wondered, how do I get a hash table into a CSV? Have I even ever done that? Now, a few commands in, and I can’t even remember why I wondered that. There was a reason, I just wish I could remember what it was. Whatever it was, I should be more likely to remember how to get a hash table into CSV when I need it after today’s post. Was on disk storage for a hash tables for some software configuration… ugh, what was it?

Anyway, let’s start by assigning a hash table to a variable. Maybe it’ll come back to me.

$HashTable = @{
    Name = 'Tommy'
    StreetName = 'Vista Pl.'
    City = 'Tucson'
}

$HashTable
Name                           Value                                                                                                      
----                           -----                                                                                                      
Name                           Tommy                                                                                                      
StreetName                     Vista Pl.                                                                                         
City                           Tucson

Now that we’ve assigned our $HashTable variable the value of our hash table, we can try and get it into a CSV. At first, someone might try the below option. Let’s see how that works.

$HashTable |
    Export-Csv -NoTypeInformation -Path .\Desktop\HashToCsv.csv

As you can see, this doesn’t work.

In order to get this to work properly, we need to use the GetEnumerator method. I seem to use this quite often. This allows us to walk though each key-pair in our hash table.

$Hash.GetEnumerator() |
    Export-Csv -NoTypeInformation -Path .\Desktop\HashToCsv2.csv

Now it’s just perfect, minus the whole Name property (column). Huh? I only expected the Keys and Values, like we’d see produced onscreen. With this in mind, let’s instead pipe to the Select-Object cmdlet before Export-Csv and get things properly filtered.

Update: It dawned on me, after I made all these screen captures, that I actually meant I wasn’t expecting to see the Key property included. Sure, it’s the same values as Name, but in a host program we’re actually accustom to seeing Name and Value, not Key and Value.

$HashTable.GetEnumerator() |
    Select-Object -Property Key,Value |
        Export-Csv -NoTypeInformation -Path .\Desktop\HashToCsv3.csv

My next logical thought was, can we use calculated properties? Can I use a different descriptor than Key and Value? You bet we can — take a look.

$HashTable.GetEnumerator() |
    Select-Object -Property @{N='Property';E={$_.Key}},
    @{N='PropValue';E={$_.Value}} |
        Export-Csv -NoTypeInformation -Path .\Desktop\HashToCsv4.csv

So yeah, there we go. I can use a hash table, saved to disk, for some sort of configuration. I still don’t remember why I wondered this originally, but in case it’s helpful, I know where to find this when I remember why I wondered.

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