array alice of [:-0] ?? | |
Beginner question! :-)
x=[1,2,3,4]
for i in range(len(x)):
print x[:-i] Quote: Quote: Quote:
>>[]
>>[1,2,3]
>>[1,2]
>>[1]
1) The x[:-0] result seems inconsistent to me;
I get the idea that -0=0, so it is taken as x[:0] -[]
2) how then should one do this basic left-recursive subsetting (easily).
Thanks.
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On 18/07/2006 11:17 PM, guthrie wrote: Quote:
Beginner question! :-)
>
x=[1,2,3,4]
for i in range(len(x)):
print x[:-i]
> Quote: Quote:
>>[]
>>[1,2,3]
>>[1,2]
>>[1]
>
1) The x[:-0] result seems inconsistent to me;
I get the idea that -0=0, so it is taken as x[:0] -[]
2) how then should one do this basic left-recursive subsetting (easily).
>
>
|>for i in range(len(x), -1, -1):
.... print x[:i]
....
[1, 2, 3, 4]
[1, 2, 3]
[1, 2]
[1]
[] | | | | re: array alice of [:-0] ??
guthrie wrote: Quote:
Beginner question! :-)
>
x=[1,2,3,4]
for i in range(len(x)):
print x[:-i]
> Quote: Quote:
>>[]
>>[1,2,3]
>>[1,2]
>>[1]
>
1) The x[:-0] result seems inconsistent to me;
I get the idea that -0=0, so it is taken as x[:0] -[]
that's what you get. Quote:
2) how then should one do this basic left-recursive subsetting (easily).
I am not sure what you mean, but replacing x[:-i] by x[:len(x)-i] you will get
continuous behavior at i==0. | | | | re: array alice of [:-0] ??
On 2006-07-18, guthrie <guthrie@mum.eduwrote: Quote:
Beginner question! :-)
>
x=[1,2,3,4]
for i in range(len(x)):
print x[:-i]
> Quote: Quote:
>[]
>[1,2,3]
>[1,2]
>[1]
>
1) The x[:-0] result seems inconsistent to me;
I get the idea that -0=0, so it is taken as x[:0] -[]
That is correct. Negative indexes are a handy shorthand, but
they can give unexpected/strange results in a number of cases. Quote:
2) how then should one do this basic left-recursive subsetting (easily).
x=[1,2,3,4]
lng = len(x)
for i in range(lng):
print x[:lng-i]
--
Antoon Pardon | | | | re: array alice of [:-0] ??
Thanks all!!
---------------------
guthrie wrote: Quote:
Beginner question! :-)
>
x=[1,2,3,4]
for i in range(len(x)):
print x[:-i]
> Quote: Quote:
>>[]
>>[1,2,3]
>>[1,2]
>>[1]
>
1) The x[:-0] result seems inconsistent to me;
I get the idea that -0=0, so it is taken as x[:0] -[]
2) how then should one do this basic left-recursive subsetting (easily).
>
Thanks.
>
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