loading an array with a csv file

[jsira2003@yahoo.com]

Typically I load a csv file into an array. Turns out I need to create the same array table but this time I want to build the array table from within powershell and not from an external file. I thought of using hash tables. I don't believe this is the best method. Then I considered building a data table. Once again I am not sure this is the best method. Do you have any suggestions how I may be able to accomplish my goal? Is there any easy way to convert a hash table to an array?

thank you,
John

[jvierra]

Easiest way is to create custom objects for each row.

[pscustomobject]@{
Col1 = 'some value'
Col2 = 'other value'
… etc ...
}

[jsira2003@yahoo.com]

When you say $array = import-csv..., what type of table is created? How does that compare to the datatable that we created. Is it an array, system.collections.arraylist, hashtable, a data table or something else?

I ask because when I tried to send the table to a routine create as a data table it failed. I suspect it might have failed due to mistyping. I haven't had time to review it yet.

thanks,
John

[jvierra]

A CSV can be imported and converted to a DataTable.

$array = Import-Csv <file>
$dt = ConvertTo-DataTable $array

What problems are you having with this?

[jsira2003@yahoo.com]

I fixed it.

After creating the table I had to convert it to an array:

[array]$motors = $table

where table is a database. It appears the = was able to convert the table to an array without any fuss. Without this step my application failed.

John

[jvierra]

If you have a single object and not an array it cannot be converted to a DataTable.

The easy protection against singletons is the following:

[array]$csv = Import-Csv <file>
$dt = ConvertTo-DataTable $array]/b]

You will also see this at time:

$csv = @(Import-Csv <file>)

So yes. You have to explicitly force a singleton to an array.

Object collections in PowerShell are not tables. They are just collections. When a command returns a singleton it will not be returned as an array except for some CmdLets that always return collections.

For a discussion of this see: https://social.technet.microsoft.com/Forums/en-US/0bbbd689-a8d3-420a-a8f3-9a03e21fd8c3/array-and-hashtables-output?forum=winserverpowershell