FindNth()

o1 = new stzString("12*45*78*90")
# the 2nd star from 4
? o1.FindNthST(2, "*", :StartingAt = 4)
# the first star from 4
? o1.FindFirstST("*", :StartingAt = 4)

o1 = new stzString("•♥••••♥••")
# the 2nd char equal to '♥' is at position 7
? o1.FindNthW(2, '@char = "♥"')
# the 2nd substring equal to '•♥•' starts at position 6
? o1.FindNthW(2, '@substring = "•♥•"')

o1 = new stzString("12♥♥♥67♥♥♥12♥♥♥")
# the 2nd from 3
? o1.FindNthST(2, "♥♥♥", :StartingAt = 3)
# the first from 5
? o1.FindFirstST("♥♥♥", :StartingAt = 5)
# the last from 6
? o1.FindLastST("♥♥♥", :StartingAt = 6)

o1 = new stzString("12♥♥♥67♥♥♥12♥♥♥")
# the first from 6
? o1.FindFirstST("♥♥♥", :StartingAt = 6)
# the last from 6
? o1.FindLastST("♥♥♥", :StartingAt = 6)
# the 2nd from 6
? o1.FindNthST(2, "♥♥♥", :StartingAt = 6)

o1 = new stzString("bla {♥♥♥} blaba bla {♥♥♥} blabla")
# the first from 8
? o1.FindFirstST("♥♥♥", :StartingAt = 8)
# the last from 8
? o1.FindLastST("♥♥♥", :Startingat = 8)
# the 2nd from 3
? o1.FindNthST(2, "♥♥♥", :StartingAt = 3)

o1 = new stzString("12♥♥♥67♥♥♥12♥♥♥")
# the 1st from position 3 is 3 itself
? o1.FindNthST(1, "♥♥♥", :StartingAt = 3)
# the next after 3
? o1.FindNext("♥♥♥", :StartingAt = 3)
# the previous before 10 must END before 10
? o1.FindPrevious("♥♥♥", :StartingAt = 10)

o1 = new stzString("12♥♥♥67♥♥♥12♥♥♥")
# the first backward from 12
? o1.FindFirstSTD("♥♥♥", :StartingAt = 12, :Backward)
# the last backward from 12
? o1.FindLastSTD("♥♥♥", :StartingAt = 12, :Backward)
# the 2nd backward from 12
? o1.FindNthSTD(2, "♥♥♥", :StartingAt = 12, :Backward)

o1 = new stzString("12♥♥♥67♥♥♥12♥♥♥")
# the 2nd backward from 10 (:Going spelling)
? o1.FindNthSTD(2, "♥♥♥", :StartingAt = 10, :Going = :Backward)
# the first backward from 14 (bare :Backward)
? o1.FindFirstSTD("♥♥♥", :StartingAt = 14, :Backward)
# the last backward from 6 (:Direction spelling)
? o1.FindLastSTD("♥♥♥", :StartingAt = 6, :Direction = :Backward)

o1 = new stzString("ab_cd_ef_gh")
# the first underscore
? o1.FindFirst("_")
# a missing star from 4
? o1.FindFirstST("*", :StartingAt = 4)
# the underscore from 3
? o1.FindFirstST("_", :StartingAt = 3)
# the last underscore
? o1.FindLast("_")
# no last star
? o1.FindLast("*")
# the 2nd underscore
? o1.FindNth(2, "_")