bruce <[EMAIL PROTECTED]> wrote:
> i need a multi dimensional array of lists...
>
> ie
> [q,a,d]
> [q1,a1,d1]
> [q2,a2,d2]
> [q3,a3,d3]
>
> which would be a (3,4) array...
Multi-dimensional arrays aren't a built in feature of python.
You can simulate them two ways
1) with a list of lists
>>> a = [
... [1,2,3],
... [4,5,6],
... [7,8,9],
... [10,11,12]
... ]
>>>
>>> print a[1][1]
5
>>> a[2][1] = 'hello'
>>> print a
[[1, 2, 3], [4, 5, 6], [7, 'hello', 9], [10, 11, 12]]
2) using a hash
>>> a = {}
>>> i = 1
>>> for x in range(4):
... for y in range(3):
... a[x,y] = i
... i = i + 1
...
>>> print a[1,1]
5
>>> a[2,1] = 'hello'
>>> print a
{(3, 2): 12, (3, 1): 11, (1, 2): 6, (1, 1): 5, (3, 0): 10, (0, 2): 3, (1, 0):
4, (0, 0): 1, (0, 1): 2, (2, 0): 7, (2, 1): 'hello', (2, 2): 9}
>>>
Option 1) is the normal way of doing it in python. However
initialising a multidimensional array always trips over beginners. Do
it like this, where 0 is the initial value.
>>> a = [ [ 0 for y in range(3)] for x in range(4) ]
>>> print a
[[0, 0, 0], [0, 0, 0], [0, 0, 0], [0, 0, 0]]
Once you've done that you can write
>>> a = [ [ 0 for y in range(3)] for x in range(4) ]
>>> i = 1
>>> for x in range(4):
... for y in range(3):
... a[x][y] = i
... i = i + 1
...
>>> print a[1][1]
5
>>> a[2][1] = 'hello'
>>> print a
[[1, 2, 3], [4, 5, 6], [7, 'hello', 9], [10, 11, 12]]
Numeric/scipy/numpy/whatever-it-is-called-today supports
multidimensional arrays too I think and that may be more appropriate
if you are doing heavy numerical work.
--
Nick Craig-Wood <[EMAIL PROTECTED]> -- http://www.craig-wood.com/nick
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