Powershell: get column number from CSV file header - powershell

Question

I need to get the column number from an imported CSV based on a particular column name ($_."Status"). Once I have the correct column number, I can assign it to a variable and use it in a foreach loop to write text to the corresponding cells. $wsSource.cells.item($tr,49) = "Added by xyz)" Note that the column position often varies from file to file.
I already have the index/row number via $tr = $source.IndexOf($row) ...but struggling with the col number.
Thanks in advance,
Jason
Incomplete code from much larger PS script that writes two different excel files in the one loop:
$source = Import-Csv $csvFile
$i = 2
foreach($row in $source.where{$_.Contacted -like "*Invalid"})
{
$tr = ($source.IndexOf($row)+2)
$wsTemp.cells.item($i,4) = $timeStamp
$wsTemp.cells.item($i,10) = $row."Last Name"
$wsSource.cells.item($tr,49) = "Added by xyz)"
$wsSource.cells.item($tr,49).Interior.ColorIndex =19
$i++
}
}
elseif ...

Answer 1

You need to create a Hashtable to map the Excel column names with their index:
# create a hash with Excel column header names and their indices
$colMax = $wsSource.UsedRange.Columns.Count
$xlHeaders = #{}
for ($col = 1; $col -le $colMax; $col++) {
$name = $wsSource.Cells.Item(1, $col).Value() # assuming the first row has the headers
$xlHeaders[$name] = $col
}
Now you can match the column from the Csv with the column index in Excel like
if (!$xlHeaders.ContainsKey('Status')) {
Write-Warning "Excel sheet does not have a column named 'Status'"
}
else {
$xlColumn = $xlHeaders['Status']
$wsSource.Cells.Item($tr, $xlColumn) = "Added by xyz)"
$wsSource.Cells.Item($tr, $xlColumn).Interior.ColorIndex = 19
}