Get the latest date - arrays

Question

I have an array that I call $data.
I want to get the earliest dates from the $data array for each host in my csv file. The user will input a host and it will find the earliest date it was modified.
Hostname LastModified
HD 9/8/2012
LOG 9/15/2004
NETMAN 12/25/2004
NETMAN 5/5/2015
LOG 1/4/2013
LOG 6/6/2011
So if they input LOG, I want it to give me the earliest date.
Created on 9/15/2004
Code:
$data= import-csv ".\Earliest Date Template.csv"
$Hostname=Read-Host "Please enter Host Name"
$data | Foreach-Object {$_."Last Modified" = [DateTime]$_."Last Modified"; $_} | Group-Object Hostname| Foreach-Object {$_.Group | Sort-Object LastModified | Select-Object -First 1}

Answer 1

Grouping them does seem like the way to go but you don't need to do that. Just sort the entire list by date then select the last option from the list (that matches the host name you are looking for).
$hostname = Read-Host "Please enter Hostname"
$data | Sort-Object {[DateTime]$_."LastModified"} | Where-Object{$_.Hostname -eq $hostname} | Select -Last 1
You might need to do some user validation but something like this seems to work with your sample data:
Please enter Hostname: log
Hostname LastModified
-------- ------------
LOG 1/4/2013
If you then only want the date it would just be a matter of expanding the value from the result.
$data |
Sort-Object {[DateTime]$_."LastModified"} |
Where-Object{$_.Hostname -eq $hostname} |
Select -Last 1 -ExpandProperty LastModified