Using Import-CSV in Powershell, ignoring commented lines - powershell

Question

I think that I must be missing something obvious because I'm trying to use Import-CSV to import CSV files that have commented out lines (always beginning with a # as the first character) at the top of the file, so the file looks like this:
#[SpecialCSV],,,,,,,,,,,,,,,,,,,,
#Version,1.0.0,,,,,,,,,,,,,,,,,,,
#,,,,,,,,,,,,,,,,,,,,
#,,,,,,,,,,,,,,,,,,,,
#[Table],,,,,,,,,,,,,,,,,,,,
Header1,Header2,Header3,Header4,Header5,Header6,Header7,...
Data1,Data2,Data3,Data4,Data5,Data6,Data7,...
I'd like to ignore those first 5 lines, but still use Import-csv to get the rest of the information nicely in to Powershell.
Thanks

Answer 1

Simple - just use Select-String to exclude commented lines with a regex, and pipe to ConvertFrom-Csv:
Get-Content <path to CSV file> | Select-String '^[^#]' | ConvertFrom-Csv
The difference between Import-Csv and ConvertTo-Csv is that the former takes input from a file, and the latter takes pipeline input, otherwise they do the same thing - convert CSV data to an array of PSCustomObjects. So, by using ConvertFrom-Csv you can do this without modifying the CSV flie or using a temp file. You can assign the results to an array or pipe to a Foreach-Object block just as you'd do with Import-Csv:
$array = Get-Content <path to CSV file> | Select-String '^[^#]' | ConvertFrom-Csv
or
Get-Content <path to CSV file> | Select-String '^[^#]' | ConvertFrom-Csv | %{
<whatever you want do with the data>
}

Answer 2

CSV has no notion of "comments" - it's just flat data. You'll need to use Get-Content and inspect each line. If a line starts with #, ignore it, otherwise process it.
If you're OK with using a temp file:
Get-content special.csv |where-object{!$_.StartsWith("#")}|add-content -path $(join-path -path $env:temp -childpath "special-filtered.csv");
$mydata = import-csv -path $(join-path -path $env:temp -childpath "special-filtered.csv");
remove-item -path $(join-path -path $env:temp -childpath "special-filtered.csv")
$mydata |format-table -autosize; #Just for illustration
Edit: Forgot about convertfrom-csv. It gets much simpler this way.
$mydata = Get-Content special.csv |
Where-Object { !$_.StartsWith("#") } |
ConvertFrom-Csv

Answer 3

If you feed convertfrom-csv csv data as an array of lines it seems to automatically filter out comments. I frequently use convertfrom-csv this way but I haven't seen it documented.
cat data.csv | convertfrom-csv #skips commented lines automagically
("co1,col2,col3", "abc,def,ghi", "#this,is,a,comment", "abc1,def1,ghi1")|convertfrom-csv
co1 col2 col3
--- ---- ----
abc def ghi
abc1 def1 ghi1
However, the following will not skip comments:
"co1,col2,col3
abc,def,ghi
#this,is,a,comment
abc1,def1,ghi1
"|convertfrom-csv
co1 col2 col3
--- ---- ----
abc def ghi
#this is a
abc1 def1 ghi1

Answer 4

Where-object will work after import-csv as well. You just have to reference the first column from csv in the clause.
e.g.:
$EscapeCharacter = '#'
$FilteredData = Import-Csv -Path "$($Home)\Documents\sample.csv" -Delimiter "`t" -Encoding UTF8 | Where-Object {$_.coll1 -notlike "$EscapeCharacter*"}
The sample of tab delimited csv:
coll1 coll2
#Kotehulky SomeValue
Cakovice OtherValue