How can I use 'contains()' method in better way in my code - arrays

Question

$source = #("1234-abc","1234-xyz","34-pqr","3456-xyz","456-pp")
$name = #()
foreach($sr in $source)
{
$array = $sr -split "-"
$ID = $array[0]
if ($sr.contains($ID))
{
$name += Sr.split("-",1) +","
}
}
expected output:
1234 contains 1234-abc, 1234-xyz
34 contains 34-pqr
3456 contains 3456-xyz
456 contains 456-pp
but, as I have used contains() 34's value is coming along with 1234 and same thing is happening with 456 and 3456.
please help me out

Answer 1

You can use Group-Object to group the strings by their prefix:
"1234-abc","1234-xyz","34-pqr","3456-xyz","456-pp" | Group-Object {$_.Split('-')[0]}
Which gives output like this:
Count Name Group
----- ---- -----
2 1234 {1234-abc, 1234-xyz}
1 34 {34-pqr}
1 3456 {3456-xyz}
1 456 {456-pp}

Answer 2

# Use | to send values to next command
#('1234-abc', '1234-xyz', '34-pqr', '3456-xyz', '456-pp', '34-abcd', 'xxxx33333') |
ForEach-Object {
# ForEach-Object will loop through each value
# $_ represents the current object
# use -match operator to check if object ($_) matches pattern. Regex is used
if ($_ -match '^(?<Id>\d+?)-(?<Value>.*)') {
# If match was successful an automatic variable called $Matches is populated
# [PSCustomObject] and hashtable #{key = value } create a new object.
# Here we create an object that contains the Id and the value previously
# found by -match.
[PSCustomObject]#{
Id = $Matches.Id
Value = $Matches.Value
}
# Not assigning the object to a variable automatically sends it out down
# the pipeline to the next command
# Could have also created the object using Select-Object and calculated properties
# shown below:
# # $Matches | Select-Object #{n = 'Id'; e = {$_.Id}}, #{n = 'Value'; e = {$_.Value}}
}
else {
# If value doesn't match the regex create an object that passes this
# down the pipeline as well
[pscustomobject]#{Id = 'No Match'; Value = $_ }
}
} |
# Group objects by Id using Group-Object
Group-Object -Property Id |
# Another ForEach-Object to process each of our new groupings
# containing our pscustomobjects with Id and Value. Since each group is
# being sent 1 at a time we can use this to display each group and the values.
# Groups will contain a Name property generated based off the property being grouped: Id
ForEach-Object {
Write-Host "** $($_.Name) **" -ForegroundColor Yellow
$_.Group.Value
}
Output will look like this
** 1234 **
abc
xyz
** 34 **
pqr
abcd
** 3456 **
xyz
** 456 **
pp
** No Match **
xxxx33333
Here is the same code as above without all the comments
#('1234-abc', '1234-xyz', '34-pqr', '3456-xyz', '456-pp', '34-abcd', 'xxxx33333') |
ForEach-Object {
if ($_ -match '^(?<Id>\d+?)-(?<Value>.*)') {
[PSCustomObject]#{Id = $Matches.Id; Value = $Matches.Value}
}
else {
[pscustomobject]#{Id = 'No Match'; Value = $_ }
}
} |
Group-Object -Property Id |
ForEach-Object {
Write-Host "** $($_.Name) **" -ForegroundColor Yellow
$_.Group.Value
}

Answer 3

$result = [System.Collections.Generic.Dictionary[String,System.Collections.Generic.List[String]]]::new([System.StringComparer]::InvariantCultureIgnoreCase)
#("1234-abc","1234-xyz","34-pqr","3456-xyz","456-pp") |
ForEach-Object {
$indexOfDelimeter = $_.indexOf('-')
$key = $_.Substring(0, $indexOfDelimeter).ToUpperInvariant()
if (-not $result.ContainsKey($key)) {
$result[$key] = [System.Collections.Generic.List[string]]::new()
}
$result[$key].Add($_)
}
Result:
# $result
Key Value
--- -----
1234 {1234-abc, 1234-xyz}
34 {34-pqr}
3456 {3456-xyz}
456 {456-pp}