[Tutor] how to make a reference to part of list?

[Kent Johnson]

Xie Chao wrote:
>    3Q very much!
>    What I really want to get is a c-style array, a pointer to the 
> beginning of part of a list (or whatever alike). for example, I want to 
> mutate part of a list, of course, I can achieve this by passing the pair 
> list and (begin, end) as parameters. but in some case, this manner 
> is quite tedious and in efficient (I think so, at least in C-style 
> language it is so)!
>     I don't wanna get the '+' operator (which is powerful tool in 
> scripting language), so I ignore this problem. thank you all the same!
>     maybe this prolem looks silly, since I've just begun to 
> study scripting language. 

Take a look at numpy, it seems to do what you want:
In [2]: from numpy import *

In [4]: a=arange(10)

In [5]: a
Out[5]: array([0, 1, 2, 3, 4, 5, 6, 7, 8, 9])

In [6]: b=a[3:5]

In [7]: b
Out[7]: array([3, 4])

In [8]: b[0]=10

In [9]: b
Out[9]: array([10,  4])

In [10]: a
Out[10]: array([ 0,  1,  2, 10,  4,  5,  6,  7,  8,  9])

http://numpy.scipy.org/

Kent