Retrieving second part of a line when first part matches exactly - powershell

Question

I used the below steps to retrieve a string from file
$variable = 'abc#yahoo.com'
$test = $variable.split('#')[0];
$file = Get-Content C:\Temp\file1.txt | Where-Object { $_.Contains($test) }
$postPipePortion = $file | Foreach-Object {$_.Substring($_.IndexOf("|") + 1)}
This results in all lines that contain $test as a substring. I just want the result to contain only the lines that exactly matches $test.
For example, If a file contains
abc_def|hf#23$
abc|ohgvtre
I just want the text ohgvtre

Answer 1

If I understand the question correctly you probably want to use Import-Csv instead of Get-Content:
Import-Csv 'C:\Temp\file1.txt' -Delimiter '|' -Header 'foo', 'bar' |
Where-Object { $_.foo -eq $test } |
Select-Object -Expand bar

Answer 2

To address the exact matching, you should be testing for equality (-eq) rather than substring (.Contains()). Also, there is no need to parse the data multiple times. Here is your code, rewritten to to operate in one pass over the data using the -split operator.
$variable = 'abc#yahoo.com'
$test = $variable.split('#')[0];
$postPipePortion = (
# Iterate once over the lines in file1.txt
Get-Content C:\Temp\file1.txt | foreach {
# Split the string, keeping both parts in separate variables.
# Note the backslash - the argument to the -split operator is a regex
$first, $second = ($_ -split '\|')
# When the first half matches, output the second half.
if ($first -eq $test) {
$second
}
}
)