lists <-> tuple

Peter Notebaert peno at
Sat Nov 5 16:47:50 CET 2005

"Jim" <mrmaple at> wrote in message 
news:1130973892.137886.170410 at
>> Tuples or lists for matrix-like functionality?
> Use lists.  Tuples are meant for small immutable sets of things that go
> together.  Lists are more like arrays, and you can assign to one
> existing element if you want.
> One exception, is a short vector is often a tuple like (x, y, z) and
> you might want to multiply that vector by your matrix.  You can convert
> a tuple to a list with   list(aTuple)  or back with  tuple(aList.)
> Even better, take a look at numarray (or numpy or scipy or scipy_core.)
> They all have really nice matrix code and there are C APIs that let
> you manipulate them.  Chances are they do everything you're intending
> to implement.
> Immutability example:
> tup = ("a", "b", "c")
> tup[1] = "g"
> Traceback (most recent call last):
>  File "<input>", line 1, in ?
> TypeError: object does not support item assignment
> lst = ["a", "b", "c"]
> lst[1] = "g"
> lst
> ['a', 'g', 'c']
> -Jim


More information about the Python-list mailing list