# Flatten a list/tuple and Call a function with tuples

beginner zyzhu2000 at gmail.com
Wed Jul 25 17:46:58 CEST 2007

```On Jul 25, 10:19 am, Stargaming <stargam... at gmail.com> wrote:
> On Wed, 25 Jul 2007 14:50:18 +0000, beginner wrote:
> > Hi,
>
> > I am wondering how do I 'flatten' a list or a tuple? For example, I'd
> > like to transform[1, 2, (3,4)] or [1,2,[3,4]] to  [1,2,3,4].
>
> A recursive function, always yielding the first element of the list,
> could do the job. See the ASPN Python Cookbook for a few implementations.http://aspn.activestate.com/ASPN/search?
> query=flatten&section=PYTHONCKBK&type=Subsection
>
> > Another question is how do I pass a tuple or list of all the aurgements
> > of a function to the function. For example, I have all the arguments of
> > a function in a tuple a=(1,2,3). Then I want to pass each item in the
> > tuple to a function f so that I make a function call f(1,2,3). In perl
> > it is a given, but in python, I haven't figured out a way to do it.
> > (Maybe apply? but it is deprecated?)
> >>> def foo(a, b, c): print a, b, c
> ...
> >>> t = (1, 2, 3)
> >>> foo(*t)
>
> 1 2 3
>
> Have a look at the official tutorial, 4.7.4http://www.python.org/doc/
> current/tut/node6.html#SECTION006740000000000000000
>
> > Thanks,
> > cg
>
> HTH,
> Stargaming

Hi Stargaming,

I know the * operator. However, a 'partial unpack' does not seem to
work.

def g():
return (1,2)

def f(a,b,c):
return a+b+c

f(*g(),10) will return an error.

Do you know how to get that to work?

Thanks,
cg

```