tiissa wrote: > Reinhold Birkenfeld wrote: >> ATSkyWalker wrote: >> >>>What's the difference between these 2 statements? >>> >>>If you have a String s="12345" >>> >>>s[len(s)::-1] = "54321" >>> >>>But >>> >>>s[len(s):0:-1] = "5432" >>> >>>Why? What's the difference? What number then can I use as the end of >>>the slice if I were to supply all 3 parameters? >> >> >> -1. > > -len(s) or less. > -1 will return an empty string. > > Actually you start from len(s)-1 (len(s) is not an index in s) and you > stop when you reach the index specified (or the end). Since -1 is the > same index as the starting one (-1~>len(s)-1, -2~>len(s)-2, > -len(s)+1~>0), you end up with an empty string. > > Therefore you have to try to reach indices lower (due to the negative > step) than the minimum valid index of your list in order to reverse it > fully.
Right, sorry. Well, I guess that's why one can leave out the index... Reinhold -- http://mail.python.org/mailman/listinfo/python-list
