Comparing pairs of arrays in Powershell - arrays

Question

I've got multiple pairs of Arrays.
The first of the pair contains multiple strings.
The second contains a timestamp belonging to the string at the same position of the first array.
Here are two pairs of arrays for an example:
#String array
M681
T9997
E61
H717
K700
#Timestamp Array
11:00
11:05
11:05
11:10
11:15
The second pair of Arrays would look like this:
#String array
B722
T732
L999
M681
I125
#Timestamp Array
11:00
11:00
11:05
11:10
11:15
I want to find matches where a string is in two pairs and then i want to measure the time difference between both entries.
Comparing the string-arrays was simply done by (Compare-Object -IncludeEqual -ReferenceObject $a_string -DifferenceObject $b_string -ExcludeDifferent).InputObject, but with this i couldnt compare the responding timestamps.
So my next idea was forging each pair together in a hashtable:
$hash = #{}
$hash.Add($a_string[$i],$a_timestamp[$i])
But i noticed that this would not work in my enviroment since both the strings and the timestamps could reoccur in one array, so setting one of them as the key of the hash would not be possible.
Next I tried creating a hashtable with an array as value and an index as key:
$hash.Add($indexNumber,#($a_string[$i],$a_timestamp[$i]))
Even though $hash.indexNumber prints out both values, i cant seem to get on of the values by $hash.indexNumber[0] / $hash.indexNumber[1]
I would appreciate if someone could tell me the best practice with this kind of situation or could tell me how I can successfully get the seperate Values of the array inside the hash and compare them to other array values in different hashes.
Kind regards,
Paxz.

Answer 1

So this is a relatively naive solution and will probably need some work to properly handle edge cases, but hopefully it will get you going in the right direction:
$arrayNames1 = #('M681','T9997','E61','H717','K700')
$arrayTimes1 = #('11:00','11:05','11:05','11:10','11:15')
$arrayNames2 = #('B722','T732','L999','M681','I125')
$arrayTimes2 = #('11:00','11:00','11:05','11:10','11:15')
function Find-AllIndexesOf{
param(
$array,
$term
)
$i = 0
foreach($item in $array){
if($item -eq $term){
$i
}
$i++
}
}
foreach($name in $arrayNames1){
if($arrayNames2.Contains($name)){
$array1Locations = Find-AllIndexesOf $arrayNames1 $name
$array2Locations = Find-AllIndexesOf $arrayNames2 $name
$i = 0
foreach($location in $array1Locations){
$thisTime1 = [datetime]$arrayTimes1[$array1Locations]
$thisTime2 = [datetime]$arrayTimes2[$array2Locations[$i]]
Write-Host ('I found a time difference for {0} that started at {1} and ended at {2} for {3} total minutes' -f $name, $thisTime1, $thisTime2, ($thisTime2 - $thisTime1).TotalMinutes)
$i++
}
}
}

Answer 2

But i noticed that this would not work in my enviroment since both the strings and the timestamps could reoccur in one array, so setting one of them as the key of the hash would not be possible.
I am unclear on why a simple hashtable does not work in your use case.
$table = #{}
for ($i = 0; $i -lt $a_string.count; $i++){
if(!$table.Contains($a_string[$i])){
$table.Add($a_string[$i], #())
$table[$a_string[$i]] += $a_timestamp[$i]
}else{
$table[$a_string[$i]] += $a_timestamp[$i]
}
}
This would generate a table mapped with Strings to times which could then be used to compare against other pairs.