discard """ joinable: false """ import std/assertions proc foo = var s:seq[string] var res = "" for i in 0..3: s.add ("test" & $i) s.add ("test" & $i) var lastname:string for i in s: var name = i[0..4] if name != lastname: res.add "NEW:" & name & "\n" else: res.add name & ">" & lastname & "\n" lastname = name doAssert res == """ NEW:test0 test0>test0 NEW:test1 test1>test1 NEW:test2 test2>test2 NEW:test3 test3>test3 """ foo()