negative indices for sequence types
Jacek Generowicz
jacek.generowicz at cern.ch
Wed Sep 17 04:43:13 EDT 2003
danbmil99 at yahoo.com (dan) hypothesizes:
> My explanation of the behavior is correct however. list[a] always
> equals list[a % len(list)]. A negative number mod N = its absolute
> value subtracted from N:
Proof by counterexample:
Python 2.2.2 (#1, Feb 8 2003, 12:11:31)
[GCC 3.2] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> s = '0123'
>>> s[-20 % len(s)]
'0'
>>> s[-20]
Traceback (most recent call last):
File "<stdin>", line 1, in ?
IndexError: string index out of range
Your explanation of the behaviour is incorrect.
QED.
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