PowerShell - filtering for unique values

Question

I have an input CSV file with a column containing information similar to the sample below:

805265 995874 805674 984654 332574 339852 

I'd like to extract unique values into a array based on the leading two characters, so using the above sample my result would be:

80, 99, 98, 33

How might I achieve this using PowerShell?

Answer 1

Use Select-Object and parameter -unique:

$values = '805265', '995874', '805674', '984654', '332574', '339852'  $values |   Foreach-Object { $_.Substring(0,2) } |   Select-Object -unique 

If conversion to int is needed, then just cast it to [int]:

$ints =   $values |   Foreach-Object { [int]$_.Substring(0,2) } |   Select-Object -unique 

Answer 2

I'd use the Group-Object cmdlet (alias group) for this:

 Import-Csv foo.csv | group {$_.ColumnName.Substring(0, 2)}  Count Name                      Group ----- ----                      -----     2 80                        {805265, 805674}     1 99                        {995874}     1 98                        {984654}     2 33                        {332574, 339852}