>>>list=[1,2,3]
>>>list[1:2]
2
>>>list[-1:1]
[]
In python, list[first:last] is return list[first,first+1,...last-1]
but list[-1:1] is return empty, why not include list[-1]?
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2 Answers
What are you expecting to return? Your -1 position in that list is 2, so your list[-1:1] is the same as list[2:1] which is empty list. You could do it with step=-1:
list[-1:1:-1]
3
Note: Usually it's not a good idea to reassign built-in variables such as list. It's better to use some othe name, i.e. l:
l = [1,2,3]
l[1]
2
l[-1]
3
l[-1:1]
[]
l[-1:1:-1]
[3]
1 Comment
Sergey Antopolskiy
"usually" is an understatement :D
in list[first,last]... the order matters
list=[1,2,3,4,5,6]
if we try list[4,2]
first = 4
and last = 2...(error..!!!!!)
it returns []
u can use
>>> list=[1,2,3,4,5,6]
>>> list[::-1]
[6, 5, 4, 3, 2, 1]
>>>
