How to perform operation on csv without writing any files

I have a script that outputs and manipulates csv files. I want to do this without writing any files. Is there a way to hold everything in variables and get the same results? I am still new at this so I want to find a better way of doing things to keep my scripts clean. Any help with formatting or restructuring the script to make it more efficient would be very much appreciated.

# Export
$parsedbody1 | Export-Csv C:\windows\temp\parsedbody.Csv

# Import and select the desired properties
Import-Csv C:\windows\temp\parsedbody.Csv | Select-Object id, startepoch, ackedepoch | Export-csv C:\windows\temp\parsedbody1.csv

# Import and add column timetoack fill with 0
Import-Csv C:\windows\temp\parsedbody1.csv | Select-Object *,@{name='timetoack';Expression={'0'}} | Export-csv C:\windows\temp\parsedbody2.csv

# ackedepoch-startepoch=timetoack
$parsedbody2 = Import-Csv -path C:\windows\temp\parsedbody2.csv
  Foreach ($field in $parsedbody2) {
  $field.timetoack = $field.ackedepoch - $field.startepoch
  }
$parsedbody2 | Export-Csv -path C:\windows\temp\parsedbody3.csv

#remove all columns other than ID and timetoack
Import-Csv -path C:\windows\temp\parsedbody3.csv | Select * -ExcludeProperty startepoch | Export-Csv -path C:\windows\temp\parsedbody4.csv
Import-Csv -path C:\windows\temp\parsedbody4.csv | Select * -ExcludeProperty ackedepoch | Export-Csv -path C:\windows\temp\parsedbody5.csv

#Divide time to ack by 60 to get minutes
$parsedbody5 = Import-Csv -path C:\windows\temp\parsedbody5.csv
  Foreach ($field in $parsedbody5) {
  $field.timetoack = $field.timetoack/60
  }
$parsedbody5 | Export-Csv -path C:\windows\temp\parsedbody6.csv

#import final csv into a variable and cleanup files
$idtta = Import-Csv -path C:\windows\temp\parsedbody6.csv

del C:\windows\temp\parsedbody.csv
del C:\windows\temp\parsedbody1.csv
del C:\windows\temp\parsedbody2.csv
del C:\windows\temp\parsedbody3.csv
del C:\windows\temp\parsedbody4.csv
del C:\windows\temp\parsedbody5.csv
del C:\windows\temp\parsedbody6.csv

Here is what is contained in $parsedbody1 usually there are several of these contained in the variable:

id                            : DS2624511
type                          : dataSourceAlert
internalId                    : LMD513444
startEpoch                    : 1694574968
endEpoch                      : 0
acked                         : True
ackedEpoch                    : 1695400492
ackedBy                       : username@domain.com
ackComment                    : Comment
rule                          : Error
ruleId                        : 2
chain                         : Error
chainId                       : 5
subChainId                    : 0
nextRecipient                 : 113
receivedList                  : {"sms":["username"],"email":["username@domain.com"]}
severity                      : 3
cleared                       : False
sdted                         : False
SDT                           : 
alertValue                    : 113.5121
threshold                     : > 60 90 120
clearValue                    : 
monitorObjectId               : 2324
monitorObjectType             : device
monitorObjectName             : devicename - ipaddress
monitorObjectGroups           :       
resourceId                    : 24773
resourceTemplateId            : 420
resourceTemplateType          : DS
resourceTemplateName          : System Uptime
instanceId                    : 2914087
instanceName                  : WinSystemUptime
instanceDescription           : 
dataPointName                 : UptimeDays
dataPointId                   : 4136
detailMessage                 : 
customColumns                 : 
enableAnomalyAlertSuppression : 
enableAnomalyAlertGeneration  : 

>Solution :

Your code can be reduced to this using a calculated property with Select-Object:

$parsedbody1 |
    Select-Object id, @{ N = 'timetoack'; E = { $_.ackedepoch - $_.startepoch }} |
    Export-Csv 'theFinalThing.csv' -NoTypeInformation

If you don’t want to export the resulting array of objects, and hold them in memory instead:

$theFinalThing = $parsedbody1 |
    Select-Object id, @{ N = 'timetoack'; E = { $_.ackedepoch - $_.startepoch }}

If above syntax is hard to understand, you might have an easier time by just using PSCustomObjects:

$parsedbody1 | ForEach-Object {
    [pscustomobject]@{
        id        = $_.id
        timetoack = $_.ackedepoch - $_.startepoch
    }
} | Export-Csv ....