I have an string array something like

Dim tester() As String = {"5,", "4,", "5_4,", "5_7,", "7_6,", "5_6_7,", "5_7_6_4,"}

Yes, there is a comma at the end of each string.

I want to find positions in array tester where string "5" exists. What I am not able to solve is if I have to find string "5_7" - the result I need is "5_6_7," and
"5_7_6_4".

So if my input is {5_7}, I am looking for all string in that array that have {5 and 7} in some form.

Is this possible to do? or is there is better way to do this ?

I have tried for like few hours now and nothing works