Python sublist not working for long

Question

I am trying to sublist an list which contains long.

a = [ -846930886, -1714636915, 424238335, -1649760492]
print(a[2:1])

This returns []. What's happening? I could find only this way of sub listing.

[424238335]. Okay. I got it. It's not the size. It's the start and end index. My bad. — tanvi, Dec 15 '17 at 08:46
What numbers exist starting at two, ending at one, and incrementing by 1? — juanpa.arrivillaga, Dec 15 '17 at 08:46

akash karothiya · Answer 1 · 2017-12-15T09:08:56.183

3

a[2:1] is not a valid slicing and will return empty list.

The correct syntax is object[start:end:inteval]. If you want to traverse in backward you should add interval

>>> print(a[2:1:-1])
[424238335]

Another approach will be with passing single index

>>> print(a[-2])
424238335

Or if you want to traverse in forward direction use :

>>> print(a[1:2])
[-1714636915]

edited Dec 15 '17 at 09:08

answered Dec 15 '17 at 08:44

akash karothiya

score 1 · Answer 2 · edited Dec 15 '17 at 08:49

1

Your sublist starts after it ends.So,

print(a[1:2])

will give you

[-1714636915].

edited Dec 15 '17 at 08:49

Naresh Kumar

answered Dec 15 '17 at 08:45

DanWheeler

2 Answers2