List slices
Cliff Crawford
cjc26 at nospam.cornell.edu
Tue Oct 31 11:12:45 EST 2000
* Daniel Klein <DanielK at aracnet.com> menulis:
| Given the list
|
| x = ['first','second','third','forth']
|
| and
|
| x[-1]
|
| returns ['forth'], it seems inconsistent that
|
| x[1:-1]
|
| returns ['second',third'] instead of the expected ['second',third','forth'].
| Can someone provide an explanation for this please?
It actually does make sense. :) -1 refers to the position in between
the elements 'third' and 'forth':
['first', 'second', 'third', | 'forth']
|
|
-> -1
So x[-1] gets the element after position -1, i.e. 'forth', while x[1:-1]
takes the elements in between positions 1 and -1, 'second' and 'third'.
Another way to remember this is, whenever you see x[:-1], think "chop
off the last element".
--
cliff crawford http://www.people.cornell.edu/pages/cjc26/
But WHERE are the turtles?
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