On Wed, 02 Sep 2009 17:36:36 -0700, Bob van der Poel <b...@mellowood.ca>
wrote:
On Sep 2, 4:27 pm, Ethan Furman <et...@stoneleaf.us> wrote:
Bob van der Poel wrote:
>>For a one-liner:
>> x[slice(*map(int, x[1:-1].split(':')))]
> Thanks.
> Almost works :)
> For s="[2]" and s="[1:2]" it's fine. But, if I have
> s = "[:2]" then I get:
>>>>x[slice(*[int(i) for i in s.strip("[]").split(":")])]
> Traceback (most recent call last):
> File "<stdin>", line 1, in <module>
> ValueError: invalid literal for int() with base 10: ''
> Similar problem with [2:].
> Ideas?
try:
start, end = s[1:-1].split(':')
except ValueError:
start = int(s[1:-1] # only one value specified
end = start+1
start = int(start) if start else 0
end = int(end) if end else len(x)
x[start:end]
~Ethan~
Yes ... I see. I'm thinking that eval() is looking very nice. If we do
it the above way we also have to check for empties using things like
[1::2] and I'm really getting confused about the possibilities :)
How about:
[untested]
s = s[1:-1] # strip the brackets
if s.count(':') == 0:
return x[int(s)]
while s.count(':') < 2:
s += ':'
start, stop, step = s.split(':')
start = int(start) if start else 0
end = int(stop) if stop else len(x)
step = int(step) if step else 1
return x[start:stop:step)
~Ethan~
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