Guidance with developing PowerShell script - powershell

Question

I am not an advanced scripter by any means, but I have a task which I need to accomplish for work. The task is to create a script which looks at two pieces of information (date and capacity utilized in bytes) from each report file that is contained in a directory. These two pieces of information are located in the same place in each report. Then, using the date value, the script can report which was the highest capacity utilized value for each month. I am thinking of having the final output be in HTML format.
There are two options for acquiring the date value. The report contains the date in the format mm/dd/yyyy in the 3rd line of text and the time is included in the file name as the Epoch time.
So far, I have put together a PowerShell script that parses the date and the capacity utilized from the body of the report. This information is then added to an array.
I am looking for guidance on which date value would be better to use (Epoch time from file name or date from body of report) and what method would be best to utilize for looking at the data for each month and reporting the highest capacity utilization per month.
Here is my script so far:
#Construct an array to use for data export
$fileDirectory = "c:\Temp"
$Array1 = #()
foreach ($file in Get-ChildItem $fileDirectory)
{
#Obtain path to each file in directory
$filePath = $fileDirectory + "\" + $file
#Get content of each file during the loop
$data = Get-Content $filePath
#Create object to enter data into Array1
$myobj = "" | Select "Date","Capacity"
$dateStr = ($data[2].Split(" "))[3]
[long]$capacityStr = ($data[19].Split(","))[2]
[single]$CapacityConv = $capacityStr
$capacityConv = ($capacityConv /= 1099511627776)
#Fill the object myobj
$myobj.date = $dateStr
$myobj.capacity = $capacityConv
#Add the object to Array1
$Array1 += $myobj
#Wipe the object
$myobj = $null
}
#After the loop, export the array to CSV file
$Array1 | export-csv "c:\Scripts\test-output.csv"
$Array1
pause

Answer 1

For the date, it's really up to you. If they're equally accurate then it's a matter of opinion.
For the capacity, I'm assuming these are daily reports given the date format, and you want the highest capacity for a given month.
Since you're creating an object containing a Date and a Capacity property for each report, using the returned array of all those values, you should be able to get the information you need like this:
$Array1 | Group-Object {([DateTime]$_.Date).ToString('MMMM')} | Select-Object Name,#{Name='MaxCap';Expression={ $_.Group.Capacity | Measure-Object -Maximum | Select-Object -ExpandProperty Maximum }}
Now this is kind of a lot so let's break it down.
Group-Object groups your array based on a property. In this case, we want to group by month, but you don't have a month property, so instead of a property name we're passing in a script block to calculate the property on the fly:
([DateTime]$_.Date).ToString('MMMM')
This casts your Date property (which is a [String]) into a [DateTime] object. Then we use .ToString('MMMM') to format it into a month name.
The result will be an array of group objects, where the Name property is the name of the group (in this case it will be the month name) and the Group property will contain all of the original objects that belonged to that group.
Piping this into Select-Object, we want the Name (the month), and then we're creating a new property on the fly named MaxCap:
$_.Group.Capacity | Measure-Object -Maximum | Select-Object -ExpandProperty Maximum
So we take the current Group (the array of all the objects for that month), then expand its Capacity property so now we have an array of all the capacities for the group.
Pipe that into Measure-Object -Maximum to get the max value, then Select-Object -ExpandProperty Maximum (because Measure-Object returns an object with a Maximum property and we just want the value).
The end result is an object with the month and the maximum capacity for that month.