SUB stripComment (s$, commentMarkers$)
    IF s$ = "" THEN RETURN
    i = INSTR(s$, commentMarkers$)
    IF i > 0 THEN
        s$ = LEFT$(s$, i - 1)
        s$ = LTRIM$((RTRIM$(s$))) '' removes both leading and trailing whitespace
    END IF
END SUB

DIM s$(1 TO 4)
s$(1) = "apples, pears # and bananas"
s$(2) = "apples, pears ; and bananas"
s$(3) = "# this is a comment"
s$(4) = "  # this is a comment with leading whitespace"

FOR i = 1 TO 4
    CALL stripComment(s$(i), "#;")
    PRINT s$(i), " => Length ="; LEN(s$(i))
NEXT i