powershell - select an object from an object array

Question

I import a CSV file containing a primary key and some data, for example

key,data
1,one
2,two
3,three
4,four
5,five

I want the data field of one record, based on the key value. here's what I do

$db=import-csv data.csv
$data=($db|?{$_.key -eq 4}).data

is there a smarter/more elegant way to write the second line ?

PS. for this time, I'm stuck with PS v2

beatcracker · Accepted Answer · 2015-10-09 23:49:10Z

1

There is more elegant way, not sure about performance though:

# Convert CSV to Hashtable
$db = Import-CSV data.csv | Group-Object -AsHashTable -AsString -Property Key

You can then get values like this:

answered Oct 9, 2015 at 23:49

beatcracker

6,9601 gold badge22 silver badges44 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

briantist · Accepted Answer · 2015-10-09 23:41:39Z

0

If you know that the keys are ascending, without gaps, and start from 1, then you could go by index (zero based):

$desiredKey = 4
$db[$desiredKey-1].data

But that seems like a dicey assumption, and the way you're doing it is probably better than that.

You could build a [hashtable] and then do direct lookups:

$hash = @{}
$db | ForEach-Object { $hash[$_.key] = $_.data }

$db[4]

answered Oct 9, 2015 at 23:41

briantist

48.3k6 gold badges94 silver badges139 bronze badges

unfortunately the keys set contains a lot of holes. I'll go with the hash table.