Specific match between two CSV files - powershell

Question

I have two CSV files like this:
CSV1:
Name
test;
test & example;
test & example & testagain;
CSV2:
Name
test1;
test&example;
test & example&testagain;
I want to compare each line of CSV1 with each line of CSV2 and, if the first 5 letters match, write the result.
I'm able to compare them but only if match perfectly:
$CSV1 = Import-Csv -Path ".\client.csv" -Delimiter ";"
$CSV2 = Import-Csv ".\client1.csv" -Delimiter ";"
foreach ($record in $CSV1) {
$result = $CSV2 | Where {$_.name -like $record.name}
$result
}

Answer 1

You can do so with Compare-Object and a custom property definition.
Compare-Object $CSV1 $CSV2 -Property {$_.name -replace '^(.{5}).*', '$1'} -PassThru
$_.name -replace '^(.{5}).*', '$1' will take the first 5 characters from the property name (or less if the string is shorter than 5 characters) and remove the rest. This property is then used for comparing the records from $CSV1 and $CSV2. The parameter -PassThru makes the cmdlet emit the original data rather than objects with just the custom property. In theory you could also use $_.name.Substring(0, 5) instead of a regular expression replacement for extracting the first 5 characters. However, that would throw an error if the name is shorter than 5 characters like in the first record from $CSV1.
By default Compare-Object outputs the differences between the input objects, so you also need to add the parameters -IncludeEqual and -ExcludeDifferent to get just the matching records.
Pipe the result through Select-Object * -Exclude SideIndicator to remove the property SideIndicator from the output.

Answer 2

foreach ($record in $CSV1) {
$CSV2 | Where {"$($_.name)12345".SubString(0, 5) -eq "$($record.name)12345".SubString(0, 5)} |
ForEach {[PSCustomObject]#{Name1 = $Record.Name; Name2 = $_.Name}}
}
or:
... | Where {($_.name[0..4] -Join '') -eq ($record.name[0..4] -Join '')} | ...
Using this Join-Object cmdlet:
$CSV1 | Join $CSV2 `
-Using {($Left.name[0..4] -Join '') -eq ($Right.name[0..4] -Join '')} `
-Property #{Name1 = {$Left.Name}; Name2 = {$Right.Name}}
All the above result in:
Name1 Name2
----- -----
test & example; test & example&testagain;
test & example & testagain; test & example&testagain;