Powershell CSV with headers to hashtable

Question

I have a csv file with a header row and I want to convert it to a Hashtable.

For example, this is my input:

#Version1.0
#Fields:ID,Data
1,data1
2,data2
3,data3

I want the output to be a hashtable where Key=ID and Value =Data.

This is what I have, but the results aren't quite what I want.

$mytable = Import-Csv -Path $filePath -Header ID,Data
$HashTable=@{}
foreach($r in $mytable)
{
    $HashTable[$r.ID]=$r.Data
}

This creates my table, but when I output it later via $str = $Hashtable | Out-String Write-Host $str

I'm getting the following:

Name                  Value
--------              -----------
#Fields:ID            Data
1                     data1
2                     data2
3                     data3

How do I get rid of the Headers being written to my hashtable? Is there a more elegant solution than sticking if ($r.ID.StartsWith("#")) { continue; }?

Thanks! -C

llamb · Accepted Answer · 2015-04-01 20:53:39Z

11

The default behavior in Import-Csv is to use the first (un-commented) line as the headers. Instead of defining the header in the command, remove "#Fields:" from the header line.

#Version1.0
ID,Data
1,data1
2,data2
3,data3

Then you can create the hashtable like this:

$mytable = Import-Csv -Path $filePath
$HashTable=@{}
foreach($r in $mytable)
{
    $HashTable[$r.ID]=$r.Data
}

Which returns:

Name                           Value
----                           -----
2                              data2
1                              data1
3                              data3

answered Apr 1, 2015 at 20:53

llamb

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Comments

Greg · Accepted Answer · 2017-05-04 15:30:14Z

7

$HashTable = @{}
Import-Csv $filePath | % { $HashTable[$_.ID] = $_.Data }

edited May 4, 2017 at 15:30

answered May 4, 2017 at 14:43

Greg

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1 Comment

bgStack15 Over a year ago

For the low cost of knowing the headers in the CSV file, this snippet does exactly what I need it to do!

Mike Fisher · Accepted Answer · 2020-05-26 23:38:29Z

3

Following down @llamb's road of using the first data line as headers, I had luck with:

PS> $mytable = Import-CSV -Path $filePath | Group-Object -AsHashTable -Property "ID"

PS> $mytable["2"]

ID Data
-- ----
2  data2

PS> $mytable["2"].Data
data2

answered May 26, 2020 at 23:38

Mike Fisher

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Comments

JPBlanc · Accepted Answer · 2013-10-30 10:53:52Z

2

You can try this :

Get-Content $filePath | where {$_ -notmatch '^#'} | ConvertFrom-Csv -Header ID,Data

It remove all the lines begining with # before readingg then as CSV lines.

answered Oct 30, 2013 at 10:53

JPBlanc

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1 Comment

mjolinor Over a year ago

I considered that, but it's not going to get you a hash table.

mjolinor · Accepted Answer · 2013-10-29 23:51:14Z

1

Don't know if it's "more elegant", but:

$mytable = Import-Csv -Path $filePath -Header ID,Data
$HashTable=@{}
foreach($r in $mytable)
{
    if ($r.ID -notlike '#*')
     {$HashTable[$r.ID]=$r.Data}
}

answered Oct 29, 2013 at 23:51

mjolinor

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Comments

pernahajder · Accepted Answer · 2016-03-04 12:59:21Z

0

just specify a delimiter. in your case:

$mytable = Import-Csv -Path $filePath -Delimiter ","

answered Mar 4, 2016 at 12:59

pernahajder

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1 Comment

Adi Inbar Sep 2 at 23:08

That creates an array of objects with two properties, not a hashtable.

Jaykul · Accepted Answer · 2015-03-14 19:13:19Z

-1

just use the 2nd line as your header:

ipcsv .\test.csv | % { $o = @{}} { $o[$_."#Fields:ID"] = $_.Data } {$o}

answered Mar 14, 2015 at 19:13

Jaykul

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