dog = {"bob": "bob"} # Single placeholder always fine "%s" % dog "%s" % {"bob": "bob"} "%s" % {**{"bob": "bob"}} "%s" % ["bob"] "%s" % ("bob",) "%s" % {"bob"} "%s" % [*["bob"]] "%s" % {"bob": "bob" for _ in range(1)} "%s" % ["bob" for _ in range(1)] "%s" % ("bob" for _ in range(1)) "%s" % {"bob" for _ in range(1)} # Multiple placeholders "%s %s" % dog "%s %s" % {"bob": "bob"} # F503 "%s %s" % {**{"bob": "bob"}} # F503 "%s %s" % ["bob"] "%s %s" % ("bob",) "%s %s" % {"bob"} "%s %s" % [*["bob"]] "%s %s" % {"bob": "bob" for _ in range(1)} # F503 "%s %s" % ["bob" for _ in range(1)] "%s %s" % ("bob" for _ in range(1)) "%s %s" % {"bob" for _ in range(1)}